Is anyone here good at aerodynamics?

[Deathslayer7]

The airfoil shown below has a chord length of 3 meters and an angle of attack of 30 degrees. Please compute the lift, drag, and moment coefficients about the quarter chord. Only the front half of the top airfoil experiences a 100 Pa downward pressure.

Picture:
http://i198.photobucket.com/albums/aa125/death_slayer7/P2.png

Problem 2:
The streamfunction for flow about a cylinder is given by the following formula. Assume that the free stream velocity is 7 m/s and that the cylinder has a radius, R, of .5 m.

psi (the stream function)= Vsubinfinity*y*(1-(R^2/r^2))

a) what are the velocity components in the x and y direction (u,v)
b) Please compute the volumetric flowrate (per unit depth) between a streamline that passes through point (x,y)=(-2 m,3 m) and (-2 m, 0 m). {Hint: The flowrate is equal to the difference in streamfunction at each point.}

r=sqrt(x^2+y^2)

I have some ideas but if anyone could help me out with this, I would greatly appreciate it.

[Gwyn chan 'r Gwyll]

I like to think I'm pretty aerodynamic. I'm damn thin, I know tha- oh. You mean math? Yeah, I know nothin' bout that! sorry...

[grimbold]

lemme get cynical avocado over here
he can probably help you

[CynicalAvocado]

i need some help with the lift part. can you give me the density of the air, velocity in feet per second, and area of the wing in sq feet?

[Archonic Energy]

have you tried asking these guys (http://www.youtube.com/watch?v=L93-7vRfxNs&ob=av3e).

sorry had to

[Tyndmyr]

Wolfram Alpha is pretty awesome at such things. Try asking it.

[Mando Knight]

i need some help with the lift part. can you give me the density of the air, velocity in feet per second, and area of the wing in sq feet?

You've got the pressure differential, you don't need those. It's just a physics/kinematics problem here. (EDIT: Actually, if you're calculating the coefficients, you probably will. Otherwise you get the force or moment per unit length.)

Resolve the pressures as two forces acting at their centers: the 100 Pa pressure will act at quarter-chord, the 200 Pa will act at half-chord. Take the difference of those two forces for the magnitude of the difference. Use that and your angle of attack to determine lift and drag. Cross the forces by their distances from the quarter chord to calculate their moments, then take that to calculate the total moment. The values you should get will be in per unit length, so don't fret too much about the units looking odd.

As to the second, give me a bit. I haven't done stream functions in a long time.

EDIT: Alright, looked at my book again. 2.b is simple to solve: evaluate the stream function at each of the two points, then subtract the first point's value from the second. The given hint tells you that that's how the problem is solved.

2.a seems incomplete: the velocity of the flow at what point? For an arbitrary point, take the derivative of the stream function with respect to position. (It all falls out nicely in cylindrical coordinates, of course) For a specific point, evaluate that velocity function at that position.

[Deathslayer7]

thanks for all the help. I went to the professor. He said it was an outdated test. Apparently he forgot about the velocity and told me if it's not given, then just leave it as "v".

But thanks for all the replies.