# Homework Help: Forces, Torques, Power etc. on a Wind Turbine

1. Mar 31, 2012

### physics4life1

1. The problem statement, all variables and given/known data

2. Relevant equations
P = 0.3*rho*A*V^3
F = 0.44*rho*A*V^2

From what I know that may help:

Shear Stress (Torsion) = T*radius/(Moment of Inertia)

3. The attempt at a solution

When we were given this problem no one in the class had the slightest clue how to solve it. I literally have no idea either but what I would guess to do is this:

Part a)

I would assume I need some formula that will incorporate a radius of the flange? Is that what the question means by flange thickness? In that case I suppose the shape of the flange would be circular? After finding a relevant formula you could distribute the stress over the number of bolts needed/required then solve for how many bolts to have and where to place them.

Part b)

I guess the 3hz would contribute to number of cycles to failure the turbine could withstand and we could solve for a max stress? But I am very confused what this part of the question is asking...any guidance?

Part c)

This part also confused me because in the beginning of the problem it says to neglect weight and inertial effects then our professor gave us numbers to use for this part. In any case I set up a free body diagram of the turbine and solved for the reacting forces. I think I got this part correct assuming he didn't try and trick us!

To anyone that can help, I know you don't do the hw for us and that is not what I am asking, however I have literally never been more confused in my life so any help and guidance will be GREATLY appreciated!

Thanks!