# Homework Help: Determine Lift

1. Oct 21, 2007

### jstrz13phys

1. The problem statement, all variables and given/known data
I have recorded raw pressures for from a wind tunnel for a NACA 0012 airfoil with 30 surface pressure taps.

I have computed Reynolds Number for 3 angles of attack.

I have computed the Pressure Coeff. for each pressure and graphed them verses the non-dimensionalized tap locations.
This is where I am stuck:
Numerically integrate the pressure distribution ( trapezoidal rule) to estimate lift.

2. Relevant equations

$$F_{N}=\int_{x=0}^{c}(p_{u}-p_{l})dx$$

$$F_{A} = \int_{x=0}^{c}(p_{u})(\frac{dy}{dx})_{u}+(p_{l})(\frac{dy}{dx})_{l}dx$$

$$L = F_{N}cos(\alpha)-F_{A}sin(\alpha)$$

F_{A} is axial force and F_{N} is normal force
Pu is upper surface pressure, Pl is lower surface.

3. The attempt at a solution

I am completely stuck.