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CL_mod_aeroPanelCoef

Aerodynamic coefficients for a flat plate (free molecular flow)

Calling Sequence

[res1, res2, ...] = CL_mod_aeroPanelCoef(v_wind, theta, temp, temp_p, m_mol_mass, ratio_spec, alpha, nsides, res)

Description

Parameters

v_wind:

Speed of the air flow relative to the plate (positive) [m/s]. (1x1 or 1xN)

theta:

Signed acute angle (in [-pi/2, pi/2]) between the wind velocity vector and the plate [rad]. (1x1 or 1xN)

temp:

Atmospheric temperature [K]. (1x1 or 1xN)

temp_p:

Temperature of the flat plate (wall) [K]. (1x1 or 1xN)

m_mol_mass:

Mean molar mass of incident flow molecules [kg/mol]. (1x1 or 1xN)

ratio_spec:

Ratio of number of molecules re-emitted specularly (between 0 and 1). (1x1 or 1xN)

alpha:

Accommodation coefficient (between 0 and 1). (1x1 or 1xN)

nsides:

(integer) Number of sides to be considered: 1 or 2. (1x1 or 1xN)

res (string):

Names of computed quantities or "all" or "all-tot". (1xP)

res1, res2, ...:

Computed quantities. (1xN)

Authors

Bibliography

See also

Examples

// --- Parameters
v_wind = 7000; // m/s
temp = 1100; // K
temp_p = 300; // K
m_mol_mass = 0.015; // kg
ratio_spec = 0.1;
alpha_k = 4;
m_mol_mass_p = 0.016; // kg
alpha = CL_mod_aeroPanelAlpha(alpha_k, m_mol_mass, m_mol_mass_p);

// --- Example 1: flat plate (one side)
theta = linspace(-%pi/2, %pi/2, 361);
res = CL_mod_aeroPanelCoef(v_wind, theta, temp, temp_p, m_mol_mass, ratio_spec, alpha, 1, "all");

scf();
plot(CL_rad2deg(theta), res.cx_abs, "r");
plot(CL_rad2deg(theta), res.cx_spec, "g");
plot(CL_rad2deg(theta), res.cx_diff, "b");
plot(CL_rad2deg(theta), res.cx, "k");
xtitle("Drag Coefficient (1 side)", "theta = oriented angle between wind velocity vector and flat plate (deg)");
CL_g_legend(gca(), ["Absorption", "Specular reemiss.", "Diffuse reemiss.", "Total"]);
CL_g_stdaxes();

scf();
plot(CL_rad2deg(theta), res.cz_abs, "r");
plot(CL_rad2deg(theta), res.cz_spec, "g");
plot(CL_rad2deg(theta), res.cz_diff, "b");
plot(CL_rad2deg(theta), res.cz, "k");
xtitle("Lift Coefficient (1 side)", "theta = oriented angle between wind velocity vector and flat plate (deg)");
CL_g_legend(gca(), ["Absorption", "Specular reemiss.", "Diffuse reemiss.", "Total"]);
CL_g_stdaxes();

// --- Example 2: computation for a sphere
// Integration over rings with velocity vector as axis of revolution
// => cx_sphere = integral from 0 -> pi of:
// [2 * pi * R * sin(phi)] * [R * d(phi)] * cx_plate(phi) / (pi * R^2)
// phi = angle between normal and -vel_wind = pi/2 - theta
// NB: Only cx matters (symmetry around velocity vector)
theta = linspace(-%pi/2, %pi/2, 51);
cx = CL_mod_aeroPanelCoef(v_wind, theta, temp, temp_p, m_mol_mass, ratio_spec, alpha, 1, "cx");
cx_sphere = intsplin(theta, 2 * cx .* cos(theta))

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