standard atmosphere
TRANSCRIPT
AE-705 Introduction to Flight Lecture 01 Capsule-01
AE-705: Introduction to Flight
STANDARD ATMOSPHERE
Udit Vohra Aerospace Engineering Department
PEC University of Technology, Chandigarh
AE-705 Introduction to Flight Lecture 01 Capsule-01
LAYOUT
• Earth’s Atmosphere
• Atmospheric Standards
• Different Altitudes
• Two magical equations
• Q Codes for altitudes
• Weather Effects
http://www.newtonsapple.org.uk/earth-as-a-magnet/
AE-705 Introduction to Flight Lecture 01 Capsule-01
ATMOSPHERE
http://www.slideshare.net/shalinipandey77985/res525-origin-of-earth-and -earth-atmosphere
AE-705 Introduction to Flight Lecture 01 Capsule-01
AEROSPACE VEHICLES
http://static1.businessinsider.com/image/5374f0df
6bb3f73f5c360e25-1200-
1715/ap090416034735.jpg https://iasmania.com/launch-vehicles-for-satellites-space-probes/
Atmospheric vehicles Space vehicles
Why do we need
to study these ?
To study the
design and
performance of
these vehicle
Lets see what I
got for you
Vehicles which fly
in earth’s
atmosphere only
Vehicles which
fly in deep space
eg -satellites
AE-705 Introduction to Flight Lecture 01 Capsule-01
ISA (International Standard Atmosphere)
Aerospace Vehicles Design and Performance determination
Simulation and Analysis
To relate
to a common reference
Properties of real atmosphere Constant
Why do we need ISA ?
Flight test Wind tunnel results A/C design and performance
Create a hypothetical model
ISA
AE-705 Introduction to Flight Lecture 01 Capsule-01
DIFFERENT ALTITUDES
What are they ?
Somebody
help..!!
AE-705 Introduction to Flight Lecture 01 Capsule-01
Geometric
Absolute
Geopotential Pressure Alt.
Temperature.
Alt.
Density Alt.
Somebody
help..!!
AE-705 Introduction to Flight Lecture 01 Capsule-01
Geometric
Absolute
Geopotential Pressure Alt.
Temperature.
Alt.
Density Alt.
Depends on whom
you ask..!!
We will study first
three for now These will be
studied later
AE-705 Introduction to Flight Lecture 01 Capsule-01
http://www.boldmethod.com/blog/lists/2017/05/the-5-types-of-flying-altitudes/
Indicated Altitude
AE-705 Introduction to Flight Lecture 01 Capsule-01
Geometric Altitude/True Altitude – altitude from sea level
http://www.boldmethod.com/blog/lists/2017/05/the-5-types-of-flying-altitudes/
Also called
GEOMETRIC ALTITUDE
AE-705 Introduction to Flight Lecture 01 Capsule-01
Absolute Altitude – Altitude from the center of earth
Anderson-Introduction%20to%20Flight-McGraw-Hill%20Science_Engineering_Math%20(2011).pdf
AE-705 Introduction to Flight Lecture 01 Capsule-01
Geopotential Altitude - variation in g is considered with the altitude
h =
Where h is the Geopotential altitude http://hemantmore.org/physics-1/p11202005/3898/
Geopotential altitude
is considered ONLY in
case of space vehicles Why not for atmospheric
vehicles??
Figure out yourself
&
report on Moodle..!!
AE-705 Introduction to Flight Lecture 01 Capsule-01
Hydrostatic Equation
https://wikis.engrade.com/energyandearthsatmospher
John%20Anderson-Introduction%20to%20Flight-
McGrawHill%20Science_Engineering_Math%20(2011).pdf
Fluid element at rest
AE-705 Introduction to Flight Lecture 01 Capsule-01
PARAMETER VARIATION WITH ALTITUDE
Pressure, temperature, density, viscosity
AE-705 Introduction to Flight Lecture 01 Capsule-01
Variation of
P and T
with
geometric
Altitude h
ttps:
//u
plo
ad.w
ikim
edia
.org
/wik
iped
ia/c
om
mo
ns/
thum
b/6
/62/C
om
par
ison_In
tern
atio
nal
_S
tandar
d_A
tmosp
her
e_sp
ac
e_div
ing.s
vg/5
76px
-Com
par
iso
n_
Inte
rnat
ion
al_S
tan
dar
d_A
tmosp
her
e_sp
ace_
div
ing.s
vg.p
ng
Lets see it layer by layer
AE-705 Introduction to Flight Lecture 01 Capsule-01
Atmospheric vehicles (fly at
about 10km ) …so we will not
consider this part
Temperature Variation with Altitude
Gradient layer
Isothermal layer
Gradient layer
JohnAnderson-Introduction%20to%20Flight-McGraw-
Hill%20Science_Engineering_Math%20(2011).pdf
AE-705 Introduction to Flight Lecture 01 Capsule-01
P & ρ variation with altitude
Two magical equations
dp= - ρgdh
p= ρRT
Gradient layer
Isothermal
AE-705 Introduction to Flight Lecture 01 Capsule-01
Sutherland’s Formula
Viscosity
https://www.google.com/search?q=sutherland+formula+for+viscosity&source=lnms&tbm=isch&sa=X&sqi=2&ved=0ahUKEwjQ8OWao5TU
AhUDq48KHb_XC9kQ_AUIBigB&biw=1408&bih=671&dpr=0.97#imgrc=Lyv9kfZ5j2KqoM:&spf=1496032614588
AE-705 Introduction to Flight Lecture 01 Capsule-01
Pressure Altitude Altitude corresponding to the pressure values in the ISA table
Here –
the theoretical
location where at 15
degrees Celsius the
altimeter setting will
equal 29.92 inches
of mercury
Temp &
pressure
corrections
http://www.boldmethod.com/blog/lists/2017/05/the-5-types-of-flying-altitudes/
AE-705 Introduction to Flight Lecture 01 Capsule-01
Pressure altitude corrected for non-standard temperature
Density Altitude
htt
ps:
//w
ww
.m0
a.co
m/c
alcu
lati
ng
-den
sity
-alt
itude/
How to read
this graph ??
AE-705 Introduction to Flight Lecture 01 Capsule-01
Altitude corresponding to the temp values in the ISA table
Temperature Altitude
https://www.aopa.org/news-and-media/all-news/2015/april/pilot/t_mm
AE-705 Introduction to Flight Lecture 01 Capsule-01
Use the geometric altitude of the tables when referring to p,
density, and temp altitudes
Pressure altitude can be different from temp altitude and
density altitude and vice-versa
These altitude might differ from geometric altitude as well
Important points
AE-705 Introduction to Flight Lecture 01 Capsule-01
OTHER STANDARD ATMOSPHERES
USA, India, Arctic, Tropical, ….
AE-705 Introduction to Flight Lecture 01 Capsule-01
Other Standard Atmospheres
https://en.wikipedia.org/wiki/U.S._Standard_Atmosphere
1976 U.S. Standard Atmosphere
AE-705 Introduction to Flight Lecture 01 Capsule-01
https://www.google.com/search?q=united+states+standard+atmosphere+1976&source=lnms&tbm=isch&sa=X&sqi=2&ved=0ahUKEwjygv3XkJTUAhUMQo8KHeYeBl0Q_AUIBigB&biw=1570&bih=748#imgrc=hi4JaikQVNPzhM:&spf=1496027490886
1976 U.S. Standard Atmosphere cont..
AE-705 Introduction to Flight Lecture 01 Capsule-01
Indian Reference Atmosphere
Valid in Indian Equatorial Zone from Surface to 80 km Data recorded in 1985
Series of tables containing data related to • Temperature (K) • Pressure (millibars) • Density (kg m-3)
https://link.springer.com/article/10.1007%2Fs00382-016-3293-2
24
32
53
64
71
AE-705 Introduction to Flight Lecture 01 Capsule-01
https://link.springer.com/article/10.1007%2Fs00382-016-3293-2
Monthly temperature profiles from 14 years of observations (2002-15)
AE-705 Introduction to Flight Lecture 01 Capsule-01
Mumbai Weather Data (Nov 2016)
Actual Data
ISA
https://www.timeanddate.com/weather/india/mumbai/historic?month=11&year=2016
Hence, Mumbai atmosphere is
ISA +14
Elevation of
Mumbai is
14 m AMSL
AE-705 Introduction to Flight Lecture 01 Capsule-01
Minimum temperature (Antarctic) = -75 oC
Maximum temperature (Somalia, South Africa) = + 65 oC
Earth’s surface Temperature varies from -75 oC to + 65 oC
Temperature as Latitude
Arctic Minimum & Tropical Maximum
https://www.google.com/#q=arctic+minimum+atmosphere&spf=14968184947
50
AE-705 Introduction to Flight Lecture 01 Capsule-01
Q CODES FOR ALTITUDES
AE-705 Introduction to Flight Lecture 01 Capsule-01
QNH
1013.2
Flight level
1013.2
Height
elevation
QFE
MSL
QNH Altitude
• Pressure measured at ground reduced to MSL pressure
• Altitude displayed AMSL
station
AE-705 Introduction to Flight Lecture 01 Capsule-01
Runway (station)
29.92’’(1013.2 hpa ) Datum SL reference Datum (adjusted)
QFE
QNH
QNE
QFE & QNE
• SL pressure corrected for
temp for specific station
• height above the station
QFE
ISA mean atm pressure at SL
Referred as Standard
QNE
AE-705 Introduction to Flight Lecture 01 Capsule-01
Weather effects
AE-705 Introduction to Flight Lecture 01 Capsule-01
Weather Effects
Turbulence
Windshear
Clouds
Microburst
Rain & Hail