# Numerical double integrals along discontinuous surfaces

1. Sep 11, 2011

### zmall88

I posted this in the aerospace engineering forum but I think it may get more replies here:

I've been trying to compute the bending-torsion coupling constants for a wing, B1, B2 and B3. The expression for this is

$\begin{bmatrix} B_1 \\ B_2 \\ B_3 \end{bmatrix} = \iint (y^2 + z^2)\begin{bmatrix} y^2 + z^2 \\ z \\ y \end{bmatrix}dydyz$

where x is in along the wingspan direction, y is along chordwise direction and z is perp. to both.

Question is: how to evaluate this integral?

I have z as a series of points (airfoil shape), where at every y, there are two z values (upper and lower surfaces).

I'm not sure this is in the correct forum or not...