ricardo tutorial

SI Tutorial, Phase 1 - Building a Single Cylinder Model
Step 1 - Starting WaveBuild, Setting General Parameters, and Creating a Simulation Title
In this step we will open WaveBuild and establish some preliminary settings that are important for every simulation.
Chapter sections Example Input File:
1.1 Starting WaveBuild .\examples\engine\TUT_si\tut_si1.wvm
1.2 Setting General Parameters

Windows:
From the Start menu select Programs > Ricardo > WAVE > WaveBuild 8.0
Linux/UNIX:
Type wb at the command prompt
Once the application opens, the WaveBuild GUI should have a blank canvas and appear as in Figure 1.
Figure 1: WaveBuild window at startup
The title bar is across the top of the WaveBuild GUI window. It lists the name of the currently open file ( NoName.wvm by default, until renamed). If changes have been made to the file and haven't yet
been saved, an asterisk (*) will appear next to the filename. See Figures 2 and 3.
Figure 2: Title bar when WaveBuild application first opens
Figure 3: Title bar with unsaved changes to the model
The pull-down menus are listed across the top of the GUI, beneath the title bar (see Figure 4). Clicking these with the left mouse button will open up menus with selection items.

New Executes the File > New... function.
Open Executes the File > Open... function.
Save Executes the File > Save function.
Undo Executes the Edit > Undo function.
Redo Executes the Edit > Redo function.
Find Executes the Edit > Find function.
Select Puts the cursor in select mode.
Place Element Puts the cursor in element placement mode, which places an instance of the element selected in the Elements Tab for every mouse click on the canvas.
Cut Executes the Edit > Cut function.
Copy Executes the Edit > Copy function.
Paste Executes the Edit > Paste function.
Constants Table Executes the Simulation > Constants > Table function.
Run Input Check Executes the Run > WAVE > Input Check function.
Run Screen Mode Executes the Run > WAVE > Screen Mode function.
Run Batch Mode Executes the Run > WAVE > Batch Mode function.
WavePost Executes the Run > WavePost function.

WNOISE Executes the Run > WNOISE function.
Text Editor Opens the Text Editor specified in the Tools > Options tab.
Favorite Application Opens the Favorite Application specified in the Tools > Options tab.
The canvas is the main portion of the WaveBuild window and where the flow network will be assembled and described (see Figure 5).
The canvas is a customizable surface. You can customize the properties for the WaveBuild canvas by selecting the Canvas Properties... option from the Edit pull-down menu or by right-clicking on the canvas background and selecting the Edit Canvas Properties... context menu item. Customizable
options include canvas size, annotation display, and grid appearance.
Figure 5: The WaveBuild canvas Figure 6: How to Edit the Canvas Properties
The Case Manager is at the bottom of the canvas. The and buttons allow you to the add and delete cases while the arrow buttons allow you to navigate between existing cases (first case , previous case , next case , last case ). The text
field tells you exactly which case you are in and how many cases there are in total. You can type directly into the text field and press enter to jump to a specific case. In any case other than Case 1, the background of the text field turns red as a reminder that you are not in Case 1. Switch back to Case 1 if you wish to make any changes to the model geometry. The Run checkbox allows you to select whether or not WAVE should execute the current case in the simulation. By default, the checkbox is checked for all new cases.
1.2 Setting General Parameters

With any new model, the first step should always be to define the general parameters for the simulation, specifically the units system to initialize all data entry. Open the General Parameters Panel by selecting General Parameters... under the Simulation pull-down menu.
For this tutorial, all units will be defined in the SI system with mm as the basic unit of length. Select SI [mm] from the Units option menu. Wherever an input is required in WaveBuild, the units for that input will be displayed next to the entry field. When a numeric input is provided, if it is in another unit than the initialized unit, the user can change the units for entry. Changing the selection in this option menu at a later point will not convert previously-entered values between units systems!
Under the Start Options section of the panel, note the toggle button next to Reinitialize Flowfield Between Cases. Turning this on will cause WAVE to start from the user-imposed initial conditions for
wall temperatures, gas temperatures, pressures, velocities, and species concentrations in every subsequent case when multiple cases are defined (Case #1 is unaffected by this setting). This option is turned off by default because in most instances the final conditions for a converged case are closer to the final conditions of the following case than the user-imposed initial conditions. Assuming this is true, each case will converge to the final solution quicker. For this tutorial, the toggle button should remain off.
In the General Parameters section of the panel, type 30 in the Simulation Duration text field. We will be simulating an engine and this number will define the number of engine cycles to simulate. Since we don't know how many cycles our simulation will take to converge, we will set a typical number for a gasoline engine and note the convergence behavior at run time. If our number is higher than required, auto-convergence will stop the simulation.
Note that the background of the Simulation Duration field turns yellow. This is because the units are listed as s for seconds and 30 seconds far exceeds the recommended value for simulation duration in the intelligent defaults settings. WAVE, by its nature, simulates fluid flow using a timebase of seconds. When a cyclic process is introduced to the simulation (such as an engine cylinder, an oscillating flow source, etc.) WaveBuild knows to change to a cyclic timebase. Once we place the engine cylinders on the canvas, this units field will automatically change to cycles and the background of the text field will change to white. "Behind the scenes" the WAVE solver will still be solving everything in a seconds timebase, but user entry fields are changed to cycles for convenience.

button to open a file browsing window and select the properties file to use. This will fill the text field with an absolute file reference, using pointed brackets, <>, to surround the entry, denoting a filename.
Figure 7: Selecting the INDOLENE tag
In WAVE, five species are used and transported throughout the model. These are Fresh Air, Vaporized Fuel, Burned Air, Burned Fuel, and Liquid Fuel; numbered Species 1 to 5 respectively. All properties for these species are defined in a single properties file (with a .fue extension) that
contains information on how the fuel and air react at different temperatures, pressures, and

concentrations. The appropriate properties file should be selected for the fuel being used in the model. For simulations using only air, any properties file may be specified since all contain information on the properties of air. Ricardo ships numerous pre-made properties files and all are selectable from the default tags list. The user can create their own file if desired by clicking on the Create Properties File button to use the pre-processor.
Note the End of Cycle Angle text field. This field is used to specify the crank angle that WAVE will use to denote the start/end of subsequent engine cycles. By default (setting of auto), WAVE uses
the IVC of cylinder #1 as the end of cycle. This is acceptable for almost all engine simulations except when VVT is employed and continuity between cases is important. In that case, a crank angle can be specified and should be just after the latest IVC for cylinder #1 in the simulation. For this tutorial, the default setting of auto is appropriate.
When finished, the General Parameters should appear as in Figure 8.
Figure 8: Completed General Parameters Panel
Click on the Convergence tab. This tab allows the user to activate the auto-convergence mechanism, which tells WAVE to end the simulation if it converges to within the specified tolerance value for the specified number of consecutive cycles (default of 1% for 1 cycle) regardless of whether or not it has reached the specified duration. Turning this option off will cause WAVE to run to the full specified duration for each case in the simulation.

For this tutorial, the toggle button should remain on and the default values are acceptable. When finished, the Convergence tab should appear as in Figure 9.
Figure 9: Convergence Tab
Press the OK button to close the General Parameters Panel and save the settings.
1.3 Creating a Simulation Title

operations on constants may be used and will be evaluated when placed inside curly brackets, { }. Pre-defined WAVE constants are convenient to use sometimes and
include $file,$case, $subcase, $fullcase, $version, and $date. Also useful are user-defined

the top of the WaveBuild canvas and is fixed in this location. When finished, the WaveBuild canvas should appear as in Figure 10, below.
Save your model
Click on the Save button in the toolbar to save the file.
The first time the file is saved, you will be prompted for a filename and directory where the file will be written (the file is saved with a .wvm extension, for "WAVE model"). You will also be prompted to add
comments for the file (this option can be deactivated via the File tab on the Options Panel located under the Tools... pull-down menu). When the save button is subsequently clicked, or if the file is not
a newly created file (opened from a pre-existing file), the currently open file will be overwritten. To save the file elsewhere or with a different name, select the Save As... option from the File pull-down
menu. Save this file with a descriptive name, such as tut_si1.wvm .
Proceed to Step 2 - Building the Flow Network on the WaveBuild Canvas
Show

Step 2 - Building the Flow Network on the WaveBuild Canvas
In this step we will layout the junction and duct entities that are required for the single cylinder model on the WaveBuild canvas.
2.1 Placing Required Junctions .\examples\engine\TUT_si\tut_si1.wvm
2.2 Connecting the Junctions with
Ducts
.\examples\engine\TUT_si\tut_si1.wps
2.1 Placing Required Junctions
The basic geometry of the system we will model in this phase is shown in Figure 1. In order to model this, we will have to represent both the intake port and exhaust port using two duct elements, one for the tapered section and one for the un-tapered section. We will use simple orifice elements to connect the two ducts (one orifice on each side of the cylinder). The open ends of the ports will be represented using standard ambient elements.
Figure 1: Single Cylinder Layout Sketch
Move the mouse over the Ambient junction icon listed in the Elements Tree. Hold down the left mouse button and drag it onto the WaveBuild Canvas, dropping it anywhere. This will place one junction of the simple ambient type onto the model canvas (see the WaveBuild HELP on how to work with the Elements Tab). To place additional junctions without continually dragging and dropping, click on the place
element + button in the toolbar across the top of the WaveBuild
GUI. The mouse pointer changes to a "+" sign when the mouse is moved over the WaveBuild canvas.
The mouse pointer is now in junction placement mode. In junction placement mode, a junction of the selected type will be placed on the canvas every time you press any mouse button. The mouse will remain in junction placement mode until you click on the
Select button on the toolbar across the top of the WaveBuild GUI or hit the Esc key to return to select mode, at which point the mouse pointer will return to appearing as an arrow when moved over the canvas.

Place two of the Ambient junctions on the canvas approximately 12 grid squares apart horizontally. Note that when placed on the canvas, junctions "snap" to the nearest grid intersection point. This behavior can be modified via the Edit > Canvas Properties... menu item.
Drag and drop two Orifice elements from the Elements Tree on the canvas between the ambient
junctions. Finally, drag and drop an Engine Cylinder element from the Elements Tree between the Orifice junctions. When finished the WaveBuild canvas should appear as in Figure 2.
Figure 2: Junctions placed on the canvas
2.2 Connecting the Junctions with Ducts

convention (remember, the Left to Right convention doesn't necessarily mean Left to Right on the screen, it is merely a coincidence in this case!). When finished, the canvas should appear as in Figure 3.
NOTE: The ducts connecting the junctions appear as yellow lines. This is an indication that some geometric property of the ducts (i.e. diameter) has not been properly defined. Also, as you connect the two ports of an orifice junction, the icon of the orifice disappears because the ducts

Save your model
This overwrites the .wvm file with the new information and backs up the previous .wvm file to a file
with the extension .wvm_bak1. WaveBuild will create up to 9 backup files with the .bak extension,
all of which can be opened and viewed using WaveBuild.
Proceed to Step 3 - Defining Ambients, Ducts, and Orifices
Step 3 - Defining Ambients, Ducts, and Orifices
In this step we will select all of the elements (ducts and junctions) on the WaveBuild canvas, and define their geometric values and initial/boundary conditions.
3.1 Defining Ambients .\examples\engine\TUT_si\tut_si1.wvm
3.2 Defining Ducts
3.1 Defining Ambients
With the general parameters defined (specifically a units system) and all of the relevant ducts and junctions placed on the canvas, it is time to define the geometric characteristics of the model as well as specify the initial conditions and boundary conditions.
We will start by defining the Ambient junctions. As stated earlier, the left-most Ambient junction will be the intake ambient. Double-click with the left mouse button on the left-most ambient junction. This will open the Ambient Panel. In the Ambient Panel, the user can specify the conditions of the ambient atmosphere (Pressure, Temperature, and Species Concentrations) as well as specify the properties of the orifice at the end of the attached duct.
Temperature and Pressure fields on the Ambient tab and all inputs on the Initial Fluid Composition tab are used to specify the fluid conditions of the atmosphere around the attached duct. The default values of 1.0 [bar] and 300[K] and a composition of 100% fresh air are suitable for this simulation and don't need to be changed. In some simulations, the user may choose to dramatically change the temperature and pressure and/or adjust the composition to model a boundary that is either not atmospheric, like the outlet of a compressor or inlet of a turbine, or is not at sea level, such as an engine operating at high altitude.
The Diameter , Discharge Coefficient, and Acoustic End Correction fields are used to model the
orifice created where the duct ends at the ambient. The Diameter field has a default value of AUTO to
assume the same diameter as the attached duct (no restriction created). The Discharge Coefficient can be set to AUTO to have WAVE calculate this value internally during the simulation. This is only
applied to flow going from the Ambient into the attached duct and should be a value between 0 and 1 if specified. The Acoustic End Correction is only used for acoustic simulations and is discussed in detail in the Acoustics Manual.
The ambient's diameter value can never be larger than the diameter of the attached duct as it would have no physical meaning, however a value of 0 (zero) makes the ambient junction behave like a closed end to the attached duct (an end-cap).
The selection of Fixed or Floating Solution Type is discussed in detail in the Acoustics tutorials. The default setting of Floating is appropriate in almost all cases and should not be changed.
For this simulation, the default values are all appropriate and we only need to change the name of the junction. Type Intake in the ID text field (name for the junction as displayed on the canvas and in the output files). When finished, the Ambient Panel should appear as in Figure 1, below. Do the same for the right-most ambient junction and type Exhaust in the ID text field.
3.2 Defining Ducts
Next we will define the ducts. Assume that all the geometric data for the system has been measured and recorded and that a labeled sketch is provided as in Figure 2. Minimally, a duct is defined by Left and Right Diameters,Length, Discretization, and Initial Conditions.
Figure 2: Single Cylinder Layout Sketch

The middle of the Duct Panel is the Schematic section which will update the drawing of the duct to reflect the entered geometric dimensions (Bend Angle is not drawn in the schematic as it has no physical meaning in a 1-D model, it is simply used to calculate a pressure loss based on the angle and bend radius). Fuel Injectors, Spray Impingement Points, and Thermocouples will also appear in the schematic if present in the duct.
The bottom of the Duct Panel is reserved for two layers of tabs which hold entry fields in which the user will specify all information relevant to that duct. Of all of those tabs, there are three of primary importance that we will use in this tutorial. Under the top level tab of Duct Data, the Dimensions tab, the Coefficients tab, and the Initial Conditions tab are particularly relevant in all ducts and are the only tabs we will be editing during the course of this tutorial (see Figure 3).
Figure 3: Required Duct Data Tabs
On the Dimensions tab, with the Shape selected as Circular , type the dimensions given for duct1 in Figure 2 into the appropriate entry fields (Left and Right Diameters and Overall Length). The engine bore for this example is 78.1 [mm] so, following the general recommendation for discretizing the model for performance simulation, set the Discretization Length to 35 [mm] (click here to read a sidebar on Discretization). When completed, theDimensions tab for duct1 should appear as in Figure 4.
Figure 4: Duct Panel Dimensions Tab for duct1

simulation. The Left and Right end Discharge Coefficients will be automatically calculated by
WAVE when left as auto based on the diameter of the duct at the relevant end and the diameter of
the neighboring duct/orifice. If desired, this can be overridden by typing in a value for the Discharge
Coefficient from 0.0 to 1.0. For the purpose of this tutorial, the default value of auto is suitable and
should not be changed. When finished, the Coefficients tab should appear as in Figure 5.
Note that the Friction and Heat Transfer Coefficients have default values of 1.0. These values are multipliers for the standard calculation. Thus values of 0.0 imply that there is no pressure loss due to friction and no heat transfer occurring along the length of the duct while values of 2.0 imply that twice the standard pressure loss due to friction and twice the standard heat transfer is occurring. These multipliers may be used as "tuning knobs" to adjust friction and heat transfer and should be changed according to the surface roughness of the material and flow conditions in the duct. Keep in mind that surface roughness will affect BOTH of these parameters and that pressure loss due to increased heat transfer can be much greater (expansion/contraction of the gas) than pressure loss due to friction!
Figure 5: Duct Panel Coefficients Tab for duct1
On the Initial Conditions tab, type the conditions given for duct1 in Figure 2 into the appropriate entry fields (Pressure, Temperature, and Wall Temperature). In the case of duct1, all of the default settings are correct for our model. When finished, the Initial Conditions tab should appear as in Figure 6.
Note that initial conditions of Pressure and Temperature need not be extremely accurate in an engine simulation as the gas will quickly move through the system and conditions will be re- calculated frequently. The initial conditions as set will be flushed out within the first few engine cycles of the simulation. Default settings of 1.0 [bar] and 300 [K] are appropriate for most engine
simulations. Turbo/Supercharged simulations should have more appropriately set conditions to reflect the "boosted" state of the fluid and avoid start-up calculation errors.
Note that if the Structural Conduction model (discussed in later tutorials) is not active for a duct, not only is the Wall Temperature value as entered the initial Wall Temperature, it is also the fixed Wall Temperature for the duration of the simulation! Thus, special attention should be paid to setting Wall Temperatures throughout the model to ensure that heat transfer is accounted for appropriately, especially in the exhaust system. If reliable wall temperature data is not available, the Structural Conduction model should be activated and the wall temperature will be calculated during the simulation to give reasonable results.
Click the OK button to close the Duct Panel for duct1. As above, edit duct2, duct3, and duct4 and enter the relevant information according to the schematic shown in Figure 2. Use a Discretization length of 35 [mm] on the intake and 40 [mm] on the exhaust. Make sure to set the Friction coefficient to 0 (zero) and the Heat Transfer coefficient to 1.5 for each duct and do not enter Bend Angles for duct2 and duct3!
Figure 6: Duct Panel Initial Conditions Tab for duct1
3.3 Defining Orifices

Click the Undo button in the toolbar to return the Right Diameter of duct1 to 35 [mm] again.
Now double-click on the orif1 junction and note the only editable fields for an orifice junction are the ID of that junction and the junction Diameter (diameter of the orifice plate) if one exists. If an orifice
junction is simply used to join two duct ends together, than the default setting of auto is sufficient. The auto setting implies that the diameter of the orifice is equal to that of the smaller of the two attached ducts. If a restriction is to be modeled, a Diameter smaller than the smallest of the two attached ducts should be used. Type 20 [mm] in the Diameter text field and hit the OK button. Note the orif1 junction now appears as if an orifice plate is reducing the diameter at the junction.
Click the Undo button in the toolbar to return the Junction Diameter to auto again. For this
tutorial all orifice junctions will have a Diameter of auto unless otherwise specified.
Orifice with no change of area
Orifice with contraction Orifice with restriction
An orifice diameter can never be larger than the diameter of the smallest attached duct as it would have no physical meaning, however a value of 0 (zero) makes the junction behave like a closed seal between the attached ducts.
When completed, the WaveBuild canvas should appear as in Figure 7.
Figure 7: Completed WaveBuild Canvas
Save your model
Proceed to Step 4 - Defining the Engine
Step 4 - Defining the Engine
In this step we will input all of the required data for the engine. The Engine currently is not an entity on the canvas. It physically would consist of all engine cylinders represented on the WaveBuild canvas (currently only one) but also includes physical sub-models for combustion, friction, heat transfer, etc.
4.1 The Geometry Tab .\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si1.wvm
4.2 The Operating Parameters Tab

Example Output File:
4.3 The Heat Transfer Tab .\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si1.wps
4.4 The Combustion Tab
4.1 The Geometry Tab
To define the engine, open the Engine General Panel by selecting Engine... from the Model pull- down menu. The Engine General Panel consists of numerous tabs, each used to define the characteristics of the engine or the physical sub-models associated with the engine.
There are four primary tabs that are important for every engine. These are Geometry, Operating Parameters, Heat Transfer , and Combustion.

On the Geometry tab, under the Configuration section enter the relevant data for this engine as shown in Table 1.
The No. of Cylinders field does not automatically update when cylinders are placed on the screen (this allows for definition of the engine before the model is built). The user must enter the correct number of engine cylinders manually.
The Strokes per Cycle field is used to define the engine as a 2-stroke or 4-stroke engine (optionally a 6- or 8-
stroke engine for research purposes).
The Engine Type field is used to enable different combustion and emission models when either SI or Diesel are selected. The Motored option allows for engine motoring simulation (engine pumping only, no combustion via cancelling all injection events).
On the Geometry tab, under the Friction Correlation section enter the relevant data for this engine as shown in Table 2.
These coefficients are used in the Chen-Flynn friction correlation model. This model is used to calculate the FMEP (Friction Mean Effective Pressure) for the engine. When data is collected in the test cell, it can be plotted and correlated using the Chen-Flynn model so that FMEP may be calculated at non-tested engine speed/load conditions. The equation to calculate FMEP in WAVE is:
FMEP = ACF + BCF(Pmax) + CCF(rpm * stroke/2) + QCF(rpm * stroke/2)2
The use of the BCF term is to account for changes in P max, which can be used to vary frictional losses across a range of engine loads. The CCF and QCF terms are used to account for changes in rpm, varying frictional losses across a range of engine speeds.
If the simulation is only to simulate tested speed/load points, the FMEP can be entered directly using only the ACF value (directly entering FMEP in the appropriate pressure units) and setting the other coefficients to 0 (zero).
When completed, the Geometry tab should appear as in Figure 1.
No. of Cylinders 1
Strokes per Cycle 4
Engine Type Spark Ignition
Compression Ratio 10.0
Table 1: Data to be entered in the Configuration fields
ACF 0.35 [bar]
Correlation fields
4.2 The Operating Parameters Tab

1). This will allow the simulated engine speed to change between cases once we add more cases in Phase 3 of the tutorial. Note that the background of the text entry field turns yellow. This is to warn the user that the value is outside of the generally acceptable range of values for the Engine Speed field. Hover over the text {SPEED} and note the tooltip that pops up, stating that the constant {SPEED} is undefined (Figure 2).
To define this constant, open the Constants Panel by clicking on the Constants Panel button in the toolbar or by selecting Simulation > Constants > Table... from the pull-down menu. No constants have yet been defined so the Constants Panel should be blank. Type SPEED under the Name column and under the Case 1 column, set a value of 6000. This will correspond to the {SPEED} value used in the Engine General Panel for Engine Speed in rpm. When completed, the Constants Panel should appear as in Figure 3. Click OK to close the Constants Panel and save the setting.
Figure 2: The Operating Parameters tab
Figure 3: The Constants Panel
Once the SPEED constant has been defined, the background of the Engine Speed text entry field should turn white to denote an acceptable value. Also note that the simulation title at the top of the WaveBuild canvas has updated to reflect the value of the SPEED constant as given in the title. Hover the mouse over the Engine Speed entry in the text field to pop up the tool tip and note that the constant is now being evaluated correctly as in Figure 4.
The Reference Pressure and Reference Temperature fields can be left as their default values of 1.0 [bar] and 298 [K] respectively. These values are used in the calculation of volumetric efficiency for the engine and may or may not correspond to the ambient conditions of the dynamometer cell when tests are performed (different companies use different practices). When completed, the Operating Parameters tab should appear as in Figure 4.
Figure 4: The Operating Parameters tab with SPEED defined
4.3 The Heat Transfer Tab

Efficiency) and when the intake valves are closed (during compression/combustion/exhaust). Adding swirl will increase the total heat transfer due to increased charge motion in the cylinder.
Modifications to the standard Woschni model have been added to compensate for varying levels of IMEP. This can be selected by changing the Woschni Model from Original (1967) to Load Compensating (1990).
For the purpose of this tutorial, enter the relevant data for this engine as shown in Table 3.
Woschni Model Original
Heat Transfer when Intake Valves are
Closed 1.0
Cylinder Head Surface Area Multiplier 1.6 (to make 7665
mm2)
Swirl Ratio 0.0
Table 3: Data to be entered in the Heat Transfer Tab

4.4 The Combustion Tab
Finally, click the Combustion tab to bring it to the front. This panel separates the Primary Model choice (required) from the Secondary Model choice (optional, layered on top of the Primary Model) and Emissions Models. The general engine cylinder in WAVE simplifies combustion. It does not use a predictive combustion model but simply models the heat release caused by combustion vs. time. Since we are modeling a spark ignition engine and selected the Spark Ignition option on the Geometry tab, we have two combustion models available to use -- the SI Wiebe and Profile models.
The Profile model is used when Heat Release vs. Crank Angle data is available directly for every speed/load point to be tested by the model. This data can be directly entered into WAVE as a table with a combustion start time and efficiency.
More widely used, however, the SI Wiebe model simply uses an S-curve function that represents the cumulative heat-release in the cylinder. The first derivative of this function is the rate of heat release. The SI Wiebe model is very commonly used and represents experimentally observed combustion heat release quite well for most situations.
Select the SI Wiebe option from the Combustion Model drop-down menu. Enter 8.0 [deg] for the Location of 50% Burn Point and 31.0 [deg] for the Combustion Duration (10-90%). Watch the plot actively update as these values are entered. The default value of 2.0 for the Exponent in Wiebe Function is appropriate for most cases. Change it and watch the shape of the burn curve change as well. For this example, 2.0 is an appropriate value and should be used. Fraction of Charge to Burn should be left at the default value of 1.0 as well. When completed, the Combustion tab should appear as in Figure 6.

Save your model
Proceed to Step 5 - Defining the Intake and Exhaust Valves
Show

Step 5 - Defining the Intake and Exhaust Valves
In this step we will define the intake and exhaust valves by specifying their lift behavior and flow restriction behavior.
5.1 Defining the Intake Valve Lift
Behavior .\examples\engine\TUT_si\tut_si1.wvm
5.2 Defining Coefficients (Flow vs. Discharge)

The connections from duct2 and duct3 to the cyl1 junction are assumed to be valves (all engine cylinder connections are assumed to be valves). The blue connection point to duct2 denotes an intake valve and the red connection point to duct3 denotes an exhaust valve. This is correct for this model but is purely coincidental . WaveBuild places engine cylinders on the screen with two connections by default. It assumes that the first connection to be used is an intake valve and the
second connection to be used is an exhaust valve. Any other valves created (by double-clicking on the cylinder junction and editing the Number of Valves field to be larger than 2) are assumed to be intake valves. This intake/exhaust status can be changed by highlighting the connection of choice and changing the Type in the drop-down menu (see Figure 1 for example of a modified Cylinder Panel). For this tutorial, the two valves created by default are suitable and the number of valves should not be changed.
Valves are defined globally, for use anywhere in the model. Anywhere a valve is present (on an engine cylinder, in a valve-specific junction, etc.) the user must tell WAVE which globally defined valve to use. This, for example, allows the user to define an intake valve once and then use it for all engine cylinders.
Figure 1: Adding Valve Connections via the Cylinder Panel

The first entry field under the Valve Parameters section of the panel is the Reference Diameter . This value is typically the inner-seat diameter (see Figure 2, right), but if the port- coefficient data has been provided in non- dimensionalized format, whatever diameter was used to non-dimensionalize the data should be entered here. For this tutorial, type in a Reference Diameter of 35 [mm]. The Heat Transfer Diameter is only required if the valve is an engine valve and the engine conduction sub- model is activated – for this tutorial, it need not be entered.
Figure 2: Valve Measurements typically used

Click on the Edit Lift Profile button to open the Valve Lift Profile Editor.
In the Valve Lift Profile Editor, data must be entered for the behavior of the valve. This behavior is described as the lift of the valve vs. time (time is entered as cam or crank angle degrees). There are numerous options for entering this data including:
Manually entering data into the array
Copying and Pasting an array from MS Excel (on PC platform)
Reading in a pre-formatted external file
Using a tag to alias a pre-formatted external file
INTAKE VALVE

For this tutorial the data has already been provided in a pre-formatted external file that is aliased in the
default active.tags file. To select this file, click on the
tag button and select the SI1INT item. Notice that the array fills automatically by reading the contents of the
file aliased in the active.tags file and a lift vs. crank
angle curve is now plotted on the screen.
Some suppliers may provide data for the lift curve in camshaft degrees (the camshaft rotates once for every two crankshaft rotations in a 4-stroke engine) so there is a Angle Type pull-down menu to adjust the units on which the data is based. Lash, if not already incorporated into the lift array data, should be entered as hot lash. The lash in the system tends to change when the engine is running hot and is reduced from the cold lash. Rocker Ratio (if necessary) may be entered as well.
The fields of primary importance are the Anchors and the Multipliers, located at the bottom of the Valve Lift Profile Editor window. The Anchors allow arbitrary alignment of the valve profile within the engine cycle. The Profile Anchor denotes a point specified in the array of angle data. The Cycle Anchor denotes another point in the engine cycle in crank angle degrees. These two points align to locate the valve lift array within the engine cycle. These anchors can be parameterized (set as constants) to allow variable valve events between cases (cam phasing).
The Multipliers are used to multiply every point in the valve array in either lift magnitude or angle duration. These can be parameterized (set as constants) to allow variable valve lift and duration between cases. The lift multiplier can also be conveniently used to adjust the units of the text file to the appropriate units for use in the model (multiply/divide to go from inches to mm, etc.).
For this tutorial, enter the following information for valve #1, the intake valve as shown below in Table 1. This aligns the 0 degree point in the array data (in Crank Angle degrees) with the330 degree point in the engine cycle, shifting the valve event over the labeled intake stroke in the plot. It also multiplies all of the lift values by 1.414. When finished, the Valve Lift Profile Editor for valve #1 should appear as in Figure 3, below.
Table 1: Intake Valve Data

Figure 3: Valve Profile for the Intake Valve
Click the OK button to save these setting and close the Valve Lift Profile Editor.
5.2 Defining Coefficients (Flow vs. Discharge)

Coefficient Profiles button to open the Flow Coefficient Profiles Editor.
Similar to the Valve Lift Profile Editor, data must be entered for the coefficients. This behavior is described as values for both the forward and reverse flowing direction (forward implies into the cylinder, reverse implies out of the cylinder) vs. the lift of the valve (non-dimensionalized by dividing the lift by the reference diameter). Again, there are numerous options for entering this data including:
Manually entering data into the array
Copying and Pasting an array from MS Excel (on PC platform)
Reading in a pre-formatted external file
Using a tag to alias a pre-formatted external file
For this tutorial the data has been provided already in a pre-formatted external file that is aliased in
the default active.tags file. To select this file, click on the tag button and select
the CFTYP option. Notice that the array fills automatically by reading the contents of the file aliased
in the active.tags file and a coefficient profile appears in the plot on the right-hand side of the
panel, see Figure 4.

This file contains information for flow coefficients as we can tell by the fact that at zero lift (zero L/D value) the coefficient has a value of 0 (zero). Flow coefficients must be entered with the first row in the array being an L/D value of 0 (zero) and forward and reverse coefficient values of 0 (zero).
WAVE can also accept discharge coefficients as input. Discharge coefficients are distinguishable by
the fact that the coefficient value at zero lift (zero L/D value) are non-zero. If the first row of the array is an L/D value of zero and the forward and reverse coefficients are non-zero, then WAVE assumes
that the array is entered as discharge coefficients. Click on the tag button and select CDTYP to display a typical discharge coefficient profile, seeFigure 5. These two profiles are derived from the
same data so either will work and is appropriate for this tutorial.
Click the OK button to save these setting and close the Profile Editor.
Click the OK button on the Lift-Valve Editor panel to save the settings for valve #1 and return to the Valve List panel.
Figure 4: Typical Flow Coefficient Profile
Figure 5: Typical Discharge Coefficient Profile

5.3 Defining the Exhaust Valve
Click the Add button again to create a second valve that will be used to model the exhaust valve.
Figure 6: The Valves List
Follow the same steps as above but use the following information for the lift profile (the coefficients can be the same as the Intake Valve). When finished, the Valve Lift Profile Editor for valve #2 (the exhaust valve) should appear as in Figure 7, below.
With both the intake valve (valve #1) and exhaust valve (valve #2) defined, the Valves List should appear as in Figure 6. Click the OK button to save these setting
and close the Valves List panel.
By default, the engine cylinder junction has picked the intake valve connection to use Valve #1 and the exhaust valve connection to use Valve #2. This is, again, coincidental . On a multi-valve engine it may be necessary to edit the engine cylinder junction and correctly specify the valve number to use for each connection.
EXHAUST VALVE
Figure 7: Profile Editor for Valve #2 (the exhaust valve)
Save your model
Proceed to Step 6 - Adding the Fuel Injector
SI Tutorial, Phase 1 - Building a Single Cylinder Model

Step 6 - Adding the Fuel Injector
In this step we will add a fuel injector, connect it to the intake port, and define the required input parameters.
6.1 Adding the Injector Element .\examples\engine\TUT_si\tut_si1.wvm
6.2 Defining the Injector
6.1 Adding the Injector Element
The single-cylinder model is almost complete – all that remains is to add a fuel injector. WAVE handles fuel injection in one of two primary ways – targeting an air-fuel ratio or injecting a specific mass of fuel. The easier of the two methods is to target an air-fuel ratio and let WAVE inject the appropriate amount of fuel based on the airflow. This is the approach used in this tutorial and in a vast majority of simulations.
Injectors can be added to duct, y-junction, or cylinder elements, but specific injectors can only attach to specific types of flow elements. From the elements tab, drag and drop a Proportional fuel injector above duct 2. The proportional type injector can connect to a duct or y-junction flow element, but not cylinder elements. A Proportional injector will always inject enough fuel to the fluid stream to match a targeted air-fuel ratio. This is the simplest type of injector and is very commonly used.
To connect the injector to the flow element, click on the injector and drag and drop a connection onto the duct2 element. This will create a connection line between the two elements (the connection line must start at the injector element and be dropped onto the duct element, you cannot create a connection between the two by starting at the duct element). When connected, the model should appear as in Figure 1.
Figure 1: Adding an Injector
6.2 Defining the Injector
Now that the injector has been added, we can edit the properties of the injector element. Double click on the injector element to open the Proportional Injector Panel.
On the Operating Point tab, all that needs to be defined is the targeted air-fuel ratio of the injector within the duct. WAVE requires a fuel-air ratio but most frequently air-fuel ratio information is provided. This is easily overcome by using WAVE's capability to perform simple mathematical operations on constants. We will define a constant named A_F and enter air-fuel ratio data in the Constants Panel, but in the text field for Fuel/Air Ratio, type {1/A_F}. This will automatically convert the air-fuel ratio to a fuel-air ratio as required.
On the Position tab, we must define where, along the length of the duct element, the injector injects fuel into the flow system (if the injector were connected to a y-junction element, this tab would be irrelevant as there is only one fluid cell in a y-junction). Type 25 [mm] into the Distance from Left End text field to move the injector to the middle of the duct (alternatively, click and drag the injector with the middle mouse button).

Click on the Composition tab, where the total composition of the fuel before injection can be
specified. If the aforementioned charge cooling effect is undesirable, then the vapor portion can be specified here. For this tutorial, the default of 1.0 for Liquid Fuel is suitable and can be left as is (100% of the injected fuel is in liquid state, 20% of that vaporized when injected).
When completed, the Proportional Injector Panel should appear as in Figures 2-5, below. Click the OK button to close the Proportional Injector Panel and save the data (when prompted to add the A_F constant to the Constants Panel, select No).
Figure 2: Completed Injector Editor

Figure 5: Completed Composition Tab

Click the OK button to close the Constants Panel.
The single-cylinder model is complete!
Save your model

Running the WAVE solver will process all of the information that has been entered into the model and produce numeric results. These results can be post-processed in WavePost to produce plots and graphics for reports and presentations.
Phase 2 Steps Example Input File:
1 Running a WAVE Input Check
.\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si1.wvm
2 Requesting Time Plots
4 Running WAVE and Understanding the .out File
5 Introduction to Post

With these five steps, we will run the WAVE solver and create some output data for postprocessing. WavePost will be used to view plots and cycle-averaged results for the model.
Show
SI Tutorial, Phase 2 - Running WAVE and Creating Time Plots in WavePost
Step 2 - Requesting Time Plots
In this step we will add requests for plots of specific data to our existing model. Time Plots are plots of results over the course of a single engine cycle (the last engine cycle in multi-cycle simulations). Time Plots should be requested whenever the user is aware of specific data they are interested in analyzing.
2.1 Duct Time Plots .\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si1.wvm
2.2 Junction Time Plots Example Output File:
2.3 System Time Plots .\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si1.wps
2.4 Multiple Plots Overlaid

Suppose we are interested in observing the pressure and temperature at the mid-point of the intake port during the engine cycle. We can request Time Plots at the intake port (duct2) and WAVE will automatically create these plots at the end of the simulation. Right-click on duct2 and select the Edit Plots... option from the pop-up menu (see Figure 1). The Duct Plot Panel will open with no plots yet defined at this location. Click on the Create Plot button to open the Duct Plot List.
Figure 1: Adding Plot to duct2
The list of plots available at this location is displayed (this list is context-sensitive and generated based on the canvas item selected). Click on the 201 Pressure plot and then, holding the Shift button to multiple-select, click on the202 Temperature plot (most valid duct plots are in the 2xx range). Click on the OK button to close the Duct Plot List and add these plots to the Existing Plots list
in the Duct Plot Panel.
The location along the length of the duct from where plots should take their data is specified under the Duct Locations region of the panel. Locations are defined by a normalized value from zero to one (left end of duct is 0, middle of duct is 0.5, right end of duct is 1). Default Locations can be defined for commonly-used locations to be specified in multiple plots (Default Locations will appear identically for all ducts when the Duct Plot Panel is opened). Custom Locations are specific locations in the selected duct where plots should take their data. Clicking on the Use All Locations button will automatically create Custom Locations for every cell in a duct. To add locations (either Default or Custom), right-click on the column header and select Insert Column Before or Insert Column After, as appropriate, from the context-menu.
Pressure and Temperature are scalar values and, in WAVE, are stored at the center of a given cell (vector values, such as velocity, are stored at cell boundaries). As there is only one cell in duct2, no location needs to be specified. The time plots will automatically be created at the 0.5 location (half- way along the duct). Specifying any other location along the length of the duct will create identical plots.

Figure 2: Duct Plot Panel with plots at duct2
Click on the OK button to close the Duct Plot Panel. Note the plot icon now hanging off of duct2. To
edit plots at this location again, simply double-click on this icon and the Duct Plot Panel will open.
2.2 Junction Time Plots
Suppose we desired to examine the combustion performance in the power cylinder during the engine cycle. We may want to create a P-V (Pressure vs. Volume) plot. Right-click on the cyl1 junction and select the Edit Plots...option to open the Junction Plot Panel. The duct plots created above will be listed in the Existing Plots list. Click on the Create Plot button to open the Junction Plot List.

list and add the plot to the Existing Plots list. Also note that an asterisk appears to the right of the plot type for any plot with the currently selected canvas item as a location.
No location within the junction needs to be specified for the plot as there is only one calculation point in a junction. When completed, the Junction Plot Panel should appear as in Figure 3, below. Click the OK button to close the Junction Plot Panel.
Figure 3: Junction Plot Panel with plot at cyl1
2.3 System Time Plots
Although there is only one cylinder in our engine, we will eventually be creating a 4-cylinder engine. To observe the behavior of the engine itself (system of cylinders grouped together), click on the Simulation pull-down menu and select the Time Plot... menu item. This will open the Time Plot Panel where plots can be created for the engine system, as well as sensors, actuators, and pins (to be discussed in more advanced tutorials).
The System Location Type should be active by default when the panel opens. Click on the Create Plot button to open the Time Plot List for the engine system.
A few engine system specific plots are available and even fewer are applicable to our system as modeled (system plots are typically in the 7xx range). Click on the 701 Engine Torque plot and click the OK button to close the list.

Figure 4: Time Plot Panel with system plot of Engine Torque
2.4 Multiple Plots Overlaid
Perhaps we wish to examine the pressure and temperature in the exhaust port and compare it to the conditions in the intake port. We could create separate plots for the duct representing the exhaust port (duct3), but it would be more useful if the data for both ports were on the same plot. Right-click on duct3 and select the Edit Plots... option from the pop-up menu. Note that the only plots in the Existing Plots list are the pressure and temperature plots from duct2. This is because these plots are
allowed at duct3 as well (a P-V plot is not sensible in a duct, nor is engine torque).
With plot 201 highlighted, click on the Add Location button to plot the pressure at duct3 on the same plot as duct2.
Do the same for plot 202 to add duct3 to the plot of temperature in duct2. Click on the Use All Locations button to request the plots at the center of both cells in duct3 (locations of 0.25 and 0.75).

Figure 5: Duct plot panel with duct2 and duct3 plots overlaid
Click the OK button to close the Duct Plot Panel. The model should appear as in Figure 6 with all
time plots added.
Save your model

Proceed to Step 3 - Requesting Post-Processing Datasets
Show

Step 3 - Requesting Post-Processing Datasets
In this step we will request that particular data that we may be interested in later be output for the entire network , as opposed to certain locations as in the case of Time Plots. This is more convenient if the user wishes to have the data (e.g. Pressure, Temperature, etc.) at numerous points throughout the network or is unsure, ahead of time, at which locations this data will be required for post-processing. It also allows the user to do more advanced post-processing to be discussed later in
this tutorial.
3.1 Basic Datasets .\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si1.wvm
3.2 Valve Datasets Example Output File:
.\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si1.wps
3.1 Basic Datasets
Suppose we are not sure, beyond the behavior in the intake and exhaust ports, which behaviors we will be interested in viewing results for at the end of the simulation. Later analysis might require extensive amounts of data that we didn't request plots for ahead of time! It may also be inconvenient to return to WaveBuild and request more plots and rerun the model, especially if the model takes a very long time to run! We can avoid some of this by requesting Post-Processing Datasets in advance.
Open the Postprocessing Output Panel by selecting the Postprocessing Output... menu item from the Simulation pull-down menu. We have yet to request any data to be output after the simulation is
run through the WAVE solver, so the Requested Datasets list should be blank. By default, the Basic models are listed, which are datasets grouped together that are always available, no matter which
junctions or physical models exist in the simulation. To request a specific dataset that we would like written to the simulation output file, highlight one by clicking on it and then click on the single arrow button pointing to the right to add it to the list of Requested Datasets (datasets can be multiple- selected by holding down the Shift key to highlight a span of datasets or the Ctrl key to highlight multiple, individual datasets). Clicking on the double-arrow button will move all datasets form a Model grouping in the the Requested Datasets list.
For this simulation, select the VELOCITY and VOLUMETRIC_FLOW datasets. When completed, the Postprocessing Output Panel should appear as in Figure 1.
Figure 1: Requesting Basic Datasets
3.2 Valve Datasets
At the top of the Postprocessing Output Panel, change the Models option menu to Valve. This will make the Available Datasets list change to those contained in the Valve subset. All subsets besides the Basic subset are available depending upon the junctions or physical sub-models included in the analysis.

Figure 2: Requesting Valve Datasets
Click on the OK button to save the changes and close the panel.
Save your model
Proceed to Step 4 - Running WAVE and understanding the .out file
Show

Step 4 - Running WAVE and Understanding the .out File
In this step we will run the model file through the WAVE solver and learn to parse the output file. In this and the following step, all output files created during the simulation will be examined and defined as to their purpose and use.
4.1 Running the Solver .\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si1.wvm
4.2 The .out File
4.1 Running the Solver

The model has been run through an input check and is all set to create the requested data for postprocessing. To run the model through the actual WAVE solver there are two options:
Run the model in screen mode by clicking on the Run Screen Mode button in the toolbar
Run the model in batch mode by clicking on the Run Batch Mode button in the toolbar
Screen mode runs the model at high priority while sending standard output to the screen. A shell will open and the simulation will pass by, printing output in real-time for the user to examine (output is also printed to the .out file).
Batch mode runs the model at reduced priority while sending standard output to the .out file. On
PC, a shell will open, noting the version of the solver being used, the window will minimize, and the simulation will run "quietly" with no output to the screen. When the simulation is finished, the prompt will return in the opened shell. On UNIX, the process is detached from the current shell (similar to executing at the shell prompt with the "&") and run in the background. No indication of the process is given. Status of the simulation can be determined using the "ps -ef" command.
If the model has been altered in any way and not yet saved (noted by the asterisk next to the filename in the title bar), WaveBuild will prompt you to first save the file before running. Run the solver using either method and close the shell (if necessary) when the simulation is complete.
4.2 The .out File
While the simulation is running, WAVE will create a temporary file with the .hlt extension. The .hlt file will not be discussed here but this file will be automatically deleted
upon successful completion of the simulation. If this file exists when the simulation completes, it usually indicates that the simulation failed while running in WAVE.
To this point, we have been building the model and saving it along the way into a file with a .wvm extension. It is a simple XML format file that can be observed in any web browser by
changing the filename extension to .xml. There should now also exist .out, .sum , .wvd , and . wps files as well (a .rp file will have also been created for reverse compatibility with an older
post-processor and will not be discussed – it is obsoleted by the . wps file).
The .out file, discussed and analyzed earlier after the input check, now contains additional data
about the simulation. Open the .out file using any common text-editor and examine.
First note the added requests for plots and datasets called out when the input file is parsed.
BAS:TIME
PLOT # 1 201 Pressure
PLOT # 2 202 Temperature
PLOT # 3 111 Linear P-V Diagram
LOCATIONS: JUNC: cyl1
BAS:DATASETS
Next, note the output from the simulation during run-time.
Row (1) gives an abbreviation for what each column of data is displaying. This information may be

Row (2) is a summary for Cylinder #1 during engine cycle 0, the start-up cycle (WAVE simulations, by default, begin at IVC for cylinder #1 unless otherwise specified in the General Parameters
panel). Only Cylinder #1 will have results for engine cycle 0.
Row (3) is a summary of engine system performance for engine cycle 0.
Rows (4+) will be a summary of every individual cylinder in the system for each engine cycle followed by a engine system summary for each cycle.
Starting at engine cycle 3, a line (8) denoting auto-convergence conditions is printed to the output. When auto-convergence conditions are satisfied (14), if the convergence detection was activated in the General Parameters panel, WAVE will run one more engine cycle and then finish the case. This happens regardless of whether or not convergence conditions are satisfied in the following engine cycle.
The column titles as labeled in row (1) relate to the lines summarizing individual cylinder
performance. They are, in order – Cylinder Number, Engine Cycle (cumulative from start of case), Timestep number (cumulative from start of case), Mass Airflow (kg/hr), Volumetric Efficiency, Exhaust Port Temperature [K], Equivalence Ratio, IMEP [bar], PMEP [bar], Indicated Horsepower [hp], Indicated Specific Fuel Consumption [g/kW*hr], Cylinder Pressure at IVC [bar], Cylinder Temperature at IVC [K], and Trapped Fuel/Air Ratio at IVC.
NC ICYC ISTEP AIR-KG/HR VOLEF TEXH PHI IMEP PMEP IHP ISFC PCYL TCYL FTR
ENG: 1 0 1 0.00 0.000 900.0 0.000 0.000 0.000 0.00 0.0000 1.013 301.1 0.00
ENG VOLEF(TOT) = 0.0000 PHI(1) = 0.000
ENG: 1 1 723 70.68 0.858 413.2 0.883 -1.235 -1.100 -3.25 -2.1073 1.575 381.0 0.606E
ENG VOLEF(TOT) = 0.8585 PHI(1) = 0.883
ENG: 1 2 1489 79.55 0.966 1278.5 0.990 11.959 -1.202 31.50 0.2304 1.569 385.3 0.680E
ENG VOLEF(TOT) = 0.9662 PHI(1) = 0.990
I*** AUTO-CONVERGENCE: Uvariance = 0.1346E-01 Pvariance = 0.1391
ENG: 1 3 2265 79.58 0.967 1353.8 0.990 12.379 -1.213 32.61 0.2227 1.569 385.8 0.680E
ENG VOLEF(TOT) = 0.9666 PHI(1) = 0.990
I*** AUTO-CONVERGENCE: Uvariance = 0.1375E-03 Pvariance = 0.3915E-01
ENG: 1 4 3041 79.57 0.966 1356.1 0.990 12.373 -1.211 32.59 0.2227 1.568 385.9 0.680E
ENG VOLEF(TOT) = 0.9664 PHI(1) = 0.990
I*** AUTO-CONVERGENCE CONDITIONS MET: Uvariance = 0.5334E-03 Pvariance = 0.4454E-02
ENG: 1 5 3817 79.56 0.966 1356.2 0.990 12.370 -1.210 32.58 0.2228 1.569 385.9 0.680E
ENG VOLEF(TOT) = 0.9663 PHI(1) = 0.990
I*** AUTO-CONVERGENCE CONDITIONS MET: Uvariance = 0.8932E-04 Pvariance = 0.1447E-02
Next, note the information on elapsed time, number of timesteps, and limiting elements in the system.
The number of timesteps can be used to calculate the average timestep size in CA° over the last cycle (CA° per cycle / #timesteps). Our engine is a 4-stroke engine so there are 720° in a single engine cycle with 776 timesteps in the last engine cycle. This yields an average timestep size of approximately 0.93° – close to the default maximum timestep size of 1° set in the General Parameters panel. Although there is no hard and fast rule, typical, well-built WAVE models won't
have a timestep below 0.1°. If the timestep is smaller than this, it is usually due to poor modeling practice (extremely small element size within the model).
The limiting element information can be useful in finding an unreasonably small Discretization Length or Overall Length (for a duct) or Volume (for a y-junction) that may be slowing the simulation down dramatically. Note in this simulation that duct4 is the limiting element, with sub-volumes 1, 2, and 4 showing up in the list
ELAPSED TIME OUTPUT: CPU TIME (IN THIS CASE) = 0.28 sec.
WALL CLOCK TIME = 0 sec.
TIME STEP OUTPUT: TOTAL STEPS IN LAST CYCLE = 776

-------------------------------------------------------------
DUCT/VOL: duct4/1 69.1 DUCT/VOL: duct4/2 11.3 DUCT/VOL: duct4/4 18.4
------------------------------------------------------------------------------------------------------------
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Duct Junction TWALL TAV PAV PMAX PMIN UMAX UMIN MACH FLOW A
[K] [K] [bar] [bar] [bar] [m/s] [m/s] NUMBER [kg/s] [cm^
duct1 Intake 300.0 299.3 0.989 1.049 0.929 110.0 -31.1 0.3195 0.02209 12.5

duct2 orif1 310.0 294.4 0.988 1.121 0.821 114.5 -23.0 0.3423 0.02209 9.6

duct3 cyl1 400.0 1243.4 0.978 1.402 0.706 808.9 -437.8 1.0000 0.02361 0.0

duct4 orif2 400.0 1107.4 0.924 1.248 0.507 859.4 -23.5 1.3088 0.02361 6.1

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NC MASS IN VOL.EFF. TRAP.RATIO IMEP PMEP IHP TEXH RES(%) EGR(%) PHI
kg/hr bar bar K
------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------
NC DPMAX TH_DPMAX HTR EVO EVC IVO IVC VOL.EFF. COMBSTART IGNDEL
------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------
AMB.VOL.EFF (AIR IN / AMB. REF.) = 0.966 TRAP.RAT. (FRESH TR./ FRESH IN ) = 1.000
DEL.EFF. (FRESH IN / PLEN. REF.) = 1.020 SCAV.RAT. (GAS IN / GAS TR. ) = 0.965
CHARG.EFF. (FRESH TR./ PLEN. REF.) = 1.020 SCAV.EFF. (FRESH TR./ GAS TR. ) = 0.965
TOT.DEL.EFF (GAS IN / PLEN. REF.) = 1.020 RESID.FR. (RESID TR./ GAS TR. ) = 0.035
EGR FR. (RESID IN / GAS IN ) = 0.000
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CRANK ANGLES [deg ATDC] VS. FUEL MASS BURNT:
NC %BURNT: 0% 1% 2% 5% 10% 25% 50% 75% 90% 95% 99%
------------------------------------------------------------------------------------------------------------
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I DISPL./CYL. [l] = 0.3928 I NUMBER OF CYLINDERS = 1.000 I
I [in^3] = 23.97 I COMPRESSION RATIO = 10.00 I EFFECTIVE CR (VC-TDC
I BORE [mm] = 78.10 I BORE/STROKE = 0.9524 I
I [in] = 3.075 I CON. ROD LENGTH[mm] = 150.0 I
I STROKE [mm] = 82.00 I WRIST PIN OFFSET[mm] = 0.000 I
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I INT. VALVE DIA.[mm] = 35.00 I EXH. VALVE DIA.[mm] = 28.00 I #1 EVO [deg]
I MAX. LIFT [mm] = 12.57 I MAX. LIFT [mm] = 8.640 I #1 EVC [deg]
I I I #1 IVO [deg]
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I RPM = 6000. I #1 INT.PORT PR[bar] = 0.9883 I #1 IGN DELAY [de
I AMB. PRESSURE [bar] = 1.000 I [inHg] = 29.27 I #1 COMB. START[de
I [inHg] = 29.61 I #1 INT.PORT TEMP[K] = 291.1 I INJ.TIMING [de
I AMB. TEMP. [K] = 298.0 I [degF] = 64.38 I MID.INJ.PRESS.[bar
I [degF] = 76.73 I #1 EXH.PORT PR[bar] = 0.9780 I [psi
I FUEL TYPE (C:H:O) C = 7.300 I [inHg] = 28.96 I INJ.DURATION [de
I H = 13.90 I I FUEL RATE [kg/hr
I O = 0.000 I PISTON VEL. [m/s] = 16.40 I (MULTI) [lbm/hr
I FUEL LHV [MJ/kg] = 43.18 I [ft/min] = 3228. I #1 FUEL / SHOT [k
I [btu/lbm] = 0.1856E+05 I I
I (A/F) STOICH = 14.56 I I 1% FUEL PWR/CYL [
I FUEL MOLEC. WEIGHT = 101.7 I I
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I INDIC. POWER [hp] = 32.58 I BRAKE POWER [hp] = 27.93 I PMEP [bar
I IND.EFFICIENCY [%] = 37.43 I BRAKE EFFICIENCY[%] = 32.09 I [psi
I IMEP(NET) [bar] = 12.37 I BMEP [bar] = 10.61 I FMEP [bar
I [psi] = 179.4 I [psi] = 153.8 I [psi
I ISFC [kg/kW/hr] = 0.2228 I BSFC [kg/kW/hr] = 0.2598 I IMEP(GROSS) [bar
I [lbm/hp/hr] = 0.3662 I [lbm/hp/hr] = 0.4272 I [psi
I IND. TORQUE [N*m] = 38.67 I BRAKE TORQUE [N*m] = 33.15 I FRICT. TORQUE [N*
I [ft*lbf] = 28.52 I [ft*lbf] = 24.45 I PUMP. TORQUE [N*
I ISAC [kg/kW/hr] = 3.275 I AUXILIARY POWER [hp] = 0.000 I #1 EXHAUST TEMP [
I [lbm/hp/hr] = 5.383 I [kW] = 0.000 I [deg
I IND. ENERGY BALANCE:(MULTI) I FRESH AIR IN[kg/hr] = 79.56 I #1 PMAX [bar
I NET PISTON WORK [%] = 37.43 I (WET) [lbm/hr] = 175.4 I [psi
I AVAIL.EXH.ENTH. [%] = 9999. I TRAPPING RATIO = 1.000 I #1 CA AT PMAX [de
I DEBIT INTK.ENTH.[%] = 9999. I VOL.EFF.(DELIVERED) = 0.9663 I #1 MAX DP/DTH [bar/de
I H. TRAN.(IN-CYL)[%] = 15.93 I #1 VOL.EFF.(PLENUM) = 0.9747 I [psi/de
I BLOWBY AT RING1 [%] = 9999. I A/F TRAPPED = 14.70 I #1 CA AT MAX DP/DTH[de
I IMBALANCE [%] = 9999. I PHI TRAPPED = 0.9903 I #1 MAX AVG.GAS T[
I PUMPING WORK [%] = -3.662 I RESIDUAL FRAC. [%] = 3.460 I [deg
I I BRAKE POWER [kW] = 20.83 I FRIC. (%FUEL ENER.
I I I H.TRAN.(IN-CYL)[k
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I NOx [ppm] = 0.000 I HC EMISSIONS(C1) [ppm] = 63.96 I CO EMISSIONS [pp
I NOx AS NO2 [g/hr] = 0.000 I [g/hr] = 2.622 I [g/hr
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I I BEFORE EVC I AFTER EVC I
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I I BEFORE EVC I AFTER EVC I I
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I I NO I NO2 I CO I
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I I NO I NO2 I CO I HC I
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Show

Step 5 - Introduction to Post-Processing and WavePost
In this step we will examine the files created by WAVE for post-processing and use WavePost to examine and create Time Plots from the simulation. We will also observe how WavePost displays Cycle Average quantities using datasets requested in WaveBuild.
5.1 The .sum File .\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si1.wvm
5.2 The .wvd File Example Output File:
5.3 The .wps File .\Ricardo\WAVE\8.0\examples\engine\TUT_si\tut_si1.wps
5.4 Time Plots in WavePost
5.5 Cycle Average Results
5.1 The .sum File
At the end of the simulation, WAVE should have created a .sum file. The .sum file is a simple ASCII
text file that can be viewed using any text editor, but is intended for use by the WavePost post- processor.
The .sum file contains a group of name=value pairs that detail the cycle-averaged results for each
case in the simulation. Cycle-averaged results are single-number values detailing results that are calculated as an average over the entire last cycle in the simulation. Examples include Torque, Power, and Fuel-Consumption (a list of what each name in the .sum file equates to can be found in

Open the .sum file and examine:
SUM:
HTR%= 15.92595 FRICT%= 5.339182 RES%= 3.459644 VOLEFD= 0.9663104 HTR= 10338.71
THEVO1= 105.0000 THEVC1= 405.0000 OVERL1= 75.00000 COMBSTART1= -24.34658 VOLEF1= 0.9663104
AFTRP1= 14.70000 PMAXSI1= 61.92454 TH_PMAX1= 14.30476 IMEPSI1= 12.36994 EGR%1= 0.000000
HTR1= 10338.71 TRAPRT1= 1.000016 PVOLEF1= 0.9747397 DPMAX1= 2.043934 TH_DPMAX1= 0.9765625
PEXH= 0.9779931 TINT= 291.1385 TEXH= 1356.193 DELEFF= 1.020265 SCAVRA= 0.9653720
DELEFT= 1.020247 EGR= -0.1722039E-04 BHP= 27.93407 BPOWKW= 20.83043 BMEPSI= 10.60529
TORQBR= 24.45019 IHP= 32.58212 IMEPSI= 12.36994 IMEPBR= 179.4108 ITORQSI= 38.66922
NMEPBR= 179.4108 GMEPSI= 13.58031 GMEPBR= 196.9657 PMEPSI= -1.210373 PMEPBR= -17.55498
FMEPBR= 25.59414 FTORQ= 5.516422 AUXPOWKW= 0.000000 PHITRAP= 0.9902628 PPMNO= 0.000000
PPMHC= 63.96400 GMHC= 0.7283791E-03 BSHC= 0.1258814 PPMCO= 0.000000 GMCO= 0.000000
HTRIVP1= 18.83508 HTCEVP1= 279.9336 HTREVP1= -124.5681 TH0%B1= -24.34658 TH1%B1= -16.48995
TH10%B1= -7.087250 TH25%B1= -0.2220210 TH50%B1= 8.000735 TH75%B1= 16.41493 TH90%B1= 23.92243
TH0%_2%B1= 9.931245 TH0%_5%B1= 13.56872 TH0%_10%B1= 17.25933 TH0%_90%B1= 48.26900 TH2%_90%B1= 38.33776
DTLduct1= 299.2815 DTRduct1= 297.5500 DPLduct1= 0.9891816 DPRduct1= 0.9873856 DHduct1= -0.1634780E
DVLduct1= 20.95363 DVRduct1= 20.97836 DFLduct1= 0.2208944E-01 DFRduct1= 0.2208986E-01 DMLduct1= 0.3194962
DTRduct2= 294.3535 DPLduct2= 0.9882348 DPRduct2= 0.9882348 DHduct2= -0.3115508E-01 DPTOTLduct2= 1.00146
DVRduct2= 20.18555 DFLduct2= 0.2208986E-01 DFRduct2= 0.2360319E-01 DMLduct2= 0.3423029 DMRduct2= 1.000000
DPLduct3= 0.9782504 DPRduct3= 0.9351169 DHduct3= 1.857011 DPTOTLduct3= 1.054536 DPTOTRduct3= 1.07270
DFLduct3= 0.2360543E-01 DFRduct3= 0.2360524E-01 DMLduct3= 1.000000 DMRduct3= 1.308751 DTLduct4= 1107.390
DPRduct4= 0.9949624 DHduct4= 2.728034 DPTOTLduct4= 1.062538 DPTOTRduct4= 1.031677 DVLduct4= 171.7042
DFRduct4= 0.2362354E-01 DMLduct4= 1.308751 DMRduct4= 0.5594955 $case= 1.000000 $subcase= 0.000000
$pi= 3.141593 A_F= 14.70000 SPEED= 6000.000
#
5.2 The .wvd File
WAVE also will create a .wvd file. The .wvd file is a binary file (not legible in a text-editor) written in
Ricardo SDF (Standard Data File) format and is also intended for use by the WavePost post- processor. Data for requested time plots and datasets are stored in the .wvd file. If necessary, this
data can be extracted by using either the SDFBrowser or the sdftoascii command-line program, both installed with WAVE. The .wvd file also stores a copy of the network layout and other key
information for post-processing. This file is vital to running the WavePost post-processor and should not be tampered with by editing, renaming, etc.
5.3 The .wps File
When any time plots are requested in WaveBuild, WAVE will create a .wps file at the end of the
analysis. The . wps file is also an XML format file that can be observed in any web browser by
changing the filename extension to.xml. It is simply a session file (template) for the WavePost post-
processor detailing what information to extract from the . wvd file for requested time plots that are
created during the WAVE simulation.
When WavePost is launched directly from WaveBuild, it will look in the working directory for a . wps file with the same prefix as the currently loaded . wvm file in WaveBuild. If it exists, the file is
opened in WavePost and the . wvd and .sum files from the same simulation are assumed to be the
results set for analysis.
5.4 Time Plots in WavePost
Launch WavePost from WaveBuild by clicking on the WavePost button in the toolbar . The WavePost GUI will open and automatically load the .wps created by WAVE (since we requested time
plots in WaveBuild). The network should appear in the main WavePost window identical to its appearance in WaveBuild (see Figure 1).
Figure 1: WavePost GUI

The Results Frame in the lower right corner of WavePost shows all results available in the current session file. Plots are categorized as Time Plots, Sweep Plots, Spatial Plots, or TCMAP Plots. The Time Plots that we requested in WaveBuild have been automatically created and are listed in the tree under the Time Plots folder. Double-click on the Pressure plot to see the result (see Figure 2). Notice that this plot has a data line for the single element in duct2 as well as both of the elements in duct3, where we decided to "Use All Locations".
Figure 2: Time Plot of Pressure in duct2 and duct3
Each plot can be individually opened and edited. Elements of the plot, such as the data line, the axes, the title, etc. are all selectable and changeable. Individual data curves can be hidden through the Curve Selector Panel (Tools > Curve Selector...). Data can also be Cut, Copied, and Pasted between plots. A single plot can also be Cloned (File > Clone) to create an exact copy of a plot to use as a template for new data.
Data can be added to a plot from the existing results ( Add > Data...) or imported from an ASCII text file, Ricardo SDF-formatted file, or, on PC, from an MS-Excel file (File > Import > Excel..., ASCII..., or SDF...). Data on an existing plot can also be exported to an Excel file (on PC) or to an
ASCII text file by selecting the File > Export... pull-down menu item.
Plots can be printed directly to a printer or to an image file by clicking on the Print button in the toolbar.
The plots that were pre-requested in WaveBuild are already created and listed under the Time Plots folder. But we also requested some Basic and Valve Datasets. This data has been stored in
the .wvd file and we can now create our own time plots using this data. We will create an overlay of
Valve Flow Coefficient (CF) and Valve Discharge Coefficient (CD) vs. non-dimensionalized valve lift (L/D).

Diameter in the Variables option menu. The X Axis Selector Panel should appear as in Figure 3,
below.
Figure 3: X Axis Selector Panel
Click the OK button to save the selections and close the panel. Back in the Time Data Panel, under
the Elements option menu, highlight the Junction Cyl1 Intake 1 option and pick Valve Flow
Coefficient in the Variables option menu. When finished, the Time Data Panel should appear as
in Figure 4.
Figure 4: Time Data Panel
Click the OK button to save the settings and close the panel. The data curve for Flow Coefficient will appear in the Time Plot and the plot title and axis labels will be automatically generated. Double-click on the plot title and edit it to read " CF and CD". Double-click on the Y-axis and edit the label to read "Valve Coefficient" (delete the word Flow). Double-click on the X-axis and edit the label to read "L/D". Double-click on the plot frame (easiest to do at the top or right-edge of the plot) and click in the Grid checkbox.
Highlight the data curve and, using the Copy and Paste toolbar buttons, paste a second data curve on the same plot. Double-click on the second data curve in the legend to open the Curve Panel. Click on the Edit Databutton and then click on the Modify Data Source button. Change the
Variable to VALVE:DISCHARGE_COEFFICIENT and click on the OK button to save the

Figure 5: CF and CD Plot for cyl1 Intake Valve
Time plots can also be made quickly by right-clicking on an element in the flow network diagram and selecting a variable to plot. Right-click on duct1 to create a time plot of Velocity at location 0.0 (Figure 6) and right-click oncyl1 to create a time plot of Pressure (Figure 7).
Figure 6: Velocity Time Plot at duct1, Location 0.0

5.5 Cycle Average Results in WavePost
Any dataset that stores data for elements (cells/junctions) which was requested in WaveBuild can be displayed as color contours on the flow network diagram. In the Results Frame in the lower right corner of WavePost, right-click on the Average folder under the Network Displays folder. This will open the Average Panel and will automatically redraw the model canvas to display the flow network as a simple scaled model; the ducts and junctions are redrawn with relative diameters displayed and color contours to represent the selected variable. Change the name to Case #1 Velocity and select the Velocity variable, then click the OK button to close the panel. This creates the Network Display in the Average folder named Case #1 Velocity.
The scale at the bottom of the window automatically sets upper and lower bounds by using the highest and lowest calculated values from the dataset. These can be controlled in the Contour Map Panel (accessible from the Average Panel, or by double-clicking on the contour bar at the bottom of the canvas) using the slider bars or by typing numerical values in the given text fields.
Figure 8: Cycle Average Velocity
Save your file

Save this WavePost session file (. wps) by selecting the Save As... option from the File pull-down
menu. It is important to save a WavePost file under a different name when it has been edited (plots created, changed, etc.) since WAVE will overwrite the file every time the solver is run. If you would like to rerun the model file and still have access to the plots and network displays you've just created save the . wps file to the same directory with a new name.

WavePost
Show
SI Tutorial, Phase 3 - Converting to a Multi- Case, 4-Cylinder Model and Sweep Plots in WavePost
A 4-cylinder model can be built using the single-cylinder model as a template. The 4-cylinder model will be analyzed over a range of operating speeds by creating a multi-case analysis.
Phase 3 Steps Optional Starting Point:
1 Copying and Pasting the Single-Cylinder Model
2 Joining the Cylinders Using a Simple Y-Junction

4 Changes in the .out and .sum Files


With these five steps, we will create a parameterized 4-cylinder model that runs un-throttled over a range of 1000-6000 rpm. We will then observe the behavior of the engine over the speed range by
creating Sweep Plots in WavePost.
Show
SI Tutorial, Phase 3 - Converting to a Multi- Case, 4-Cylinder Model and Sweep Plots in WavePost
Step 1 - Copying and Pasting the Single-Cylinder Model
Time and effort can be saved when creating our 4-cylinder model by using the existing single-cylinder model as a template. Copy and Paste functionality can be used to create three copies of the single- cylinder network, including the attached ducts representing the ports. The engine information then needs to be updated to reflect the addition of three new cylinders.
1.1 Detaching the Ambient Junctions
1.2 Copying and Pasting the Network


The single-cylinder model currently has Ambient junctions at both ends, named Intake and Exhaust. We don't need to include these when replicating the engine
network. These ambient junctions can be detached and moved aside for the time being.
Middle-click on the end of duct1 that is attached to the Intake ambient. Holding the middle-mouse button down, drag the end of duct1 out onto the canvas and release the mouse button. This will detach the duct from the ambient. Repeat for the end of duct4 attached to the Exhaust ambient.
Using the middle mouse button, drag the Intake ambient further to the left, to move it out of the way. Repeat for the Exhaust ambient, moving it further to the right. When finished, the model should appear as in Figure 1.
Figure 1: Ambients Detached from Ducts
1.2 Copying and Pasting the Network
The engine-cylinder network, with the attached ducts representing the intake and exhaust ports, is identical for all four cylinders in the engine. We can therefore copy and paste the existing single- cylinder network three times to create the other cylinders in our 4-cylinder engine. Using the left mouse button, draw a box around the ducts and engine-cylinder network to select the entire system (be careful not to draw the box around the ambient junctions). All of the selected items within the box will be highlighted in red. Click on the Copy button in the toolbar . Then click on the Paste
button in the toolbar and the mouse pointer will become a crosshair icon. Click on the canvas
beneath the cyl1 junction and a duplicate network will be created. Click on the Paste button and place the duplicate network two more times to create four identical duct/junction networks to represent all four engine-cylinders. Note that the ducts and junctions have all been numbered sequentially.

Figure 2: Canvas Properties panel

1.3 Creating an Engine Block Icon
Adding an Engine Block icon to the canvas will provide a clickable and selectable object, enabling direct access to the Engine General Panel (previously accessed thr

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