# Homework Help: Drag calculation based on kinetic theory, flux

1. Feb 2, 2010

### orbitsnerd

1. The problem statement, all variables and given/known data
A flat plate is orbiting at an altitude of 250 km around the earth, at an angle of attack &Beta;=45 degrees. Assume that the atmosphere is composed of only atomic oxygen which reflect from the surface diffusely. Calculate the lift and drag if it has an area of 10 M2.

Cd~2.2
n=1x1015/m3
T=975 K
&Beta;=45 degrees
A=10 m2
mo=2.67 x 10-26 kg
vo=7.8 x 103 m/s
&Theta;=&Tau;=1
&Theta; upper=135 degrees
&Theta; lower=45 degrees

2. Relevant equations

I cannot use the basic CD, CL equations. I need to use a set of boundary condition equations based on kinetic theory.
CL=4&Epsilon;/&radic;(&Pi;) *vth[/SUB/vd * sin(&Beta;)*cos(&Beta;) exp (-vd*sin(&Beta;/vth[/SUB)^2)+....etc
and a similar equation for CD

3. The attempt at a solution

I have drifting gas equations, stationary gas equations and a ton more.

Pn/Pinf=((1+&Epsilon;)/sqrt(&Pi;))*(vd cos theta/vth)....

&Tau;/Pinf=(1-&Epsilon;)/sqrt(&Pi;)*vd sin(&Theta;)...

q/mninf(2kTinf/m)^(3/2)=alphac(1-&Epsilon;)/(4*sqrt&Pi;)...

Any help here?
Thanks!