Path: SC/Disturbances
% Computes the aerodynamic force using surface accommodation coefficients.
User inputs a data structure specifying a set of planar areas. The
coefficients may be scalars, a function, or provided by a built-in function
which is a fit to experimental data for N2 on aluminum (Fredo).
A coefficient function should have the form:
[sigmaN,sigmaT] = FCoeff( cosAlpha )
where cosAlpha is the dot product of the velocity vector and the area
normal vector. The sign convention is for outward normals and velocity is
that of the spacecraft or object.
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Form:
FAeroSurfaceAccommodation; % demo of a cube
[f,cD,cL] = FAeroSurfaceAccommodation( u, rho, t, m, d ) % built-in
[f,cD,cL] = FAeroSurfaceAccommodation( u, rho, t, m, d, sigmaN, sigmaT )
[f,cD,cL] = FAeroSurfaceAccommodation( u, rho, t, m, d, fSigma )
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Inputs
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u (3,:) Velocity vector (m/sec)
rho (1,1) Atmospheric Density (kg/m^3)
t (1,1) Atmospheric Temperature (K)
m (1,1) Mean molecular weight (kg/mol)
d (.) Plate data structure
.area (1,:) Areas
.normal (3,:) Normals
.temperature (1,:) Temperatures
sigmaN (1,1) Normal coefficient
sigmaT (1,1) Tangential coefficient
-- or --
fSigma (*) Function handle, optional
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Outputs
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force (3,1) Total force (N)
cD (1,1) Equivalent coefficent of drag
cL (1,1) Equivalent coefficent of lift
f (3,:) Element forces
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References: Richard Michael Fredo, "A Numerical Procedure for
Calculating the Aerodynamic Coefficients for Complex
Spacecraft Configurations in Free-Molecular Flow,"
Pennsylvania State University, Masters thesis, 1980.
Fredo and Kaplan, "Procedure for Obtaining Aerodynamic
Properties of Spacecraft," J. Spacecraft Vol. 18 No. 4,
July-August 1981.
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See also FAeroSurfaceAccommodation>AccommodationCoefficients
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SC: Environs/MolWt2R Common: Graphics/Plot2D Math: Linear/Cross Math: Linear/Dot Math: Linear/DupVect Math: Linear/Mag Math: Linear/Unit
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