Lapse Rate Model
Implement lapse rate model for atmosphere
Libraries:
Aerospace Blockset /
Environment /
Atmosphere
Description
The Lapse Rate Model block implements the mathematical representation of the lapse rate atmospheric equations for ambient temperature, pressure, density, and speed of sound for the input geopotential altitude. You can customize this atmospheric model by specifying atmospheric properties.
The ISA Atmosphere Model and Lapse Rate Model blocks are identical blocks. When configured for ISA Atmosphere Model, the block implements ISA values. When configured for Lapse Rate Model, the block implements the mathematical representation of lapse rate atmospheric equations.
The Lapse Rate Model block icon displays the input and output metric units.
Limitations
Below the geopotential altitude of 0 km and above the geopotential altitude of the tropopause, temperature and pressure values are held.
Density and speed of sound are calculated using a perfect gas relationship.
Ports
Input
Output
Parameters
Algorithms
These equations define the troposphere:
These equations define the tropopause (lower stratosphere):
where:
T 0 | Absolute temperature at mean sea level in kelvin (K) |
ρ 0 | Air density at mean sea level in kg/m 3 |
P 0 |
Static pressure at mean sea level in N/m 2 |
h | Altitude in m |
hts | Height of the troposphere in m |
T | Absolute temperature at altitude h in kelvin (K) |
ρ |
Air density at altitude h in kg/m 3 |
P |
Static pressure at altitude h in N/m 2 |
a |
Speed of sound at altitude h in m/s 2 |
L | Lapse rate in K/m |
R | Characteristic gas constant J/kg-K |
γ | Specific heat ratio |
g |
Acceleration due to gravity in m/s 2 |
References
[1] U.S. Standard Atmosphere., Washington, D.C.: U.S. Government Printing Office, 1976.
Extended Capabilities
Version History
Introduced before R2006a