STANDARD ATMOSPHERE Udit Vohra Aerospace Engineering Department - - PowerPoint PPT Presentation

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

https://upload.wikimedia.org/wikipedia/commons/thumb/6/62/Comparison_International_Standard_Atmosphere_spac e_diving.svg/576px-Comparison_International_Standard_Atmosphere_space_diving.svg.png

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

• f 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

https://www.m0a.com/calculating-density-altitude/

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