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ISA Atmosphere Model

Implement International Standard Atmosphere (ISA)

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  • 库:

  • Aerospace Blockset / Environment / Atmosphere

  • ISA Atmosphere Model block

Description

TheISA Atmosphere Modelblock implements the mathematical representation of the international standard atmosphere values for ambient temperature, pressure, density, and speed of sound for the input geopotential altitude.

TheISA Atmosphere ModelandLapse Rate Modelblocks are identical blocks. When configured forISA Atmosphere Model, the block implements ISA values. When configured forLapse Rate Model, the block implements lapse rate values.

TheISA Atmosphere Modelblock icon displays the input and output port labels in 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

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Geopotential height, specified as a scalar or array.

Data Types:double

Output

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Temperature, returned as a scalar or array, in K.

Data Types:double

Speed of sound, returned as a scalar or array, in m/s.

Data Types:double

Air pressure, returned as a scalar or array, in Pa.

Data Types:double

Air density, returned as scalar or array, in kg/m3.

Data Types:double

Parameters

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Customize various atmospheric parameters to be different from the ISA values. Selecting this check box converts the block fromISA Atmosphere ModeltoLapse Rate Model.

Dependencies

Selecting this check box enables the parameters:

  • 重力加速度(m / s ^ 2)

  • Ratio of specific heats

  • Characteristic gas constant (J/Kg/K)

  • 递减率(K /米)

  • Height of troposphere (m)

  • tropopau高度se (m)

  • Air density at mean sea level (Kg/m^3)

  • Ambient pressure at mean sea level (N/m^2)

  • Lowest altitude (m)

Programmatic Use

Block Parameter:custom
Type: character vector
Values:'off'|'on'
Default:'off'

Acceleration from gravity (g). in m/s2, specified as double scalar.

Dependencies

This parameter is enabled when theChange atmospheric parameterscheck box is selected.

Programmatic Use

Block Parameter:g
Type: character vector
Values: double scalar
Default:9.80665

Ratio of specific heatsγ, specified as a double value.

Dependencies

This parameter is enabled when theChange atmospheric parameterscheck box is selected.

Programmatic Use

Block Parameter:gamma
Type: character vector
Values: double scalar
Default:1.4

Characteristic gas constant (R), specified as double scalar, in J/Kg/K.

Dependencies

This parameter is enabled when theChange atmospheric parameterscheck box is selected.

Programmatic Use

Block Parameter:R
Type: character vector
Values: double scalar
Default:287.0531

Lapse rate of the troposphere, specified as double scalar, in K/m.

Dependencies

This parameter is enabled when theChange atmospheric parameterscheck box is selected.

Programmatic Use

Block Parameter:L
Type: character vector
Values: double scalar
Default:0.0065

Height of the troposphere (range of decreasing temperatures), specified as double scalar, in m.

Dependencies

This parameter is enabled when theChange atmospheric parameterscheck box is selected.

Programmatic Use

Block Parameter:h_trop
Type: character vector
Values: double scalar
Default:11000

Height of the tropopause (range of constant temperature), specified as double scalar, in m.

Dependencies

This parameter is enabled when theChange atmospheric parameterscheck box is selected.

Programmatic Use

Block Parameter:h_strat
Type: character vector
Values: double scalar
Default:20000

Air density at mean sea level, specified as double scalar, in Kg/m3.

Dependencies

This parameter is enabled when theChange atmospheric parameterscheck box is selected.

Programmatic Use

Block Parameter:rho0
Type: character vector
Values: double scalar
Default:1.225

Ambient pressure at mean sea level, specified as double scalar, in N/m2.

Dependencies

This parameter is enabled when theChange atmospheric parameterscheck box is selected.

Programmatic Use

Block Parameter:P0
Type: character vector
Values: double scalar
Default:101325

Ambient temperature at mean sea level (T0), specified as double scalar, in K.

Dependencies

This parameter is enabled when theChange atmospheric parameterscheck box is selected.

Programmatic Use

Block Parameter:K
Type: character vector
Values: double scalar
Default:101325

Lowest altitude above which temperature and pressure lapse, specified as double scalar, in m.Lowest altitude (m)must be belowtropopau高度se.

Dependencies

This parameter is enabled when theChange atmospheric parameterscheck box is selected.

Programmatic Use

Block Parameter:h0
Type: character vector
Values: double scalar
Default:0

References

[1]U.S. Standard Atmosphere., Washington, D.C.: U.S. Government Printing Office, 1976.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced before R2006a

See Also

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