2015-2016 fall akm 204e fluid mechanicskircave/fluid_mech/fld_mech_ppt.pdf · 2015-2016 fall akm...
TRANSCRIPT
FLUIDSSOLIDS
Borrowed from: http://trivedichemistry.com/WebMovie/1Chap1.htm
THE CARCRASH PROBLEM
Cansolids “flow”?
THE CARCRASH PROBLEM
Vcar=18m/s
III
III
Borrowed from: http://www.geekologie.com/2007/04/mclaren-f1-crash-test.php
THE CARCRASH PROBLEM
0
5
10
15
20
0 1 2 3 4 5
V(m/s)
t (s)
Vı
Vıı
0
5
10
15
20
1.98 2 2.02 2.04 2.06
V(m/s)
t (s)
Vı
VııaI>>aII !
CHANGE IN THE VOLUME OFACONEBY PARTIALDERIVATIVES
▸ Classification of Forces:
1. Surface Forces —> Stresses (force per unit area)
A. Normal Stress
B. Shear (Tangential) Stress
2. Body Forces
FUNDAMENTAL EQUATIONS OF FLUID MECHANICS
�!F = m ·�!K
F = � ·An
F = ⌧ ·At
V.Ş. Özgür Kırca [email protected]
WHATWEHAVESEENSOFAR:
1. UnitSystems (SI,MKfS,…)
2. DimensionalHomogeneity
3. EmpiricalEquationsvs.TheoreticalEquations
4. SpecificMass&SpecificWeight
5. SolidMechanicsvs.FluidMechanics• PhysicalPropertiesofFluids• ContinuumAssumption• Flow=AdditionalNon-linearTermstoAcceleration*
6. Forcesonabody
WHATWEWILLSEETODAY:
1. Viscosity(Fluidresistanceagainstshearstress)• Newton’sLawofViscosity• Newtonianvs.Non-newtonian Fluids• ExpressionsofKinematicandDynamicViscosity• ViscosityinLiquidsandGases
à External ForcesonaBodyà StressonaPoint(reviewataglance)
2. Statics,KinematicsandDynamics
3. Compressibility (Fluidresistanceagainstnormalstress/pressure)
4. Hydrostatics• Pressure• HydrostaticPressureLawandItsApplications• CalculationofPressureForces
STRESSONAPOINT:3D SignConvention
STRESSONAPOINT:2D SignConvention
σy
σy
σxσx