Commercial Airplane Design Principles

Appendix C

Airfoil and Wing Theory and Analysis

C.1 Linearized potential flow

Small disturbance theory assumes that the inviscid velocity field over a thin wing at small angle of attack is only slightly perturbed from the free stream velocity so that the velocity components are given by

Here the velocity components u, v, and w are in the free stream direction x, spanwise direction y, and the normal to the x–y plane direction z, respectively. The velocity perturbations are characterized by the following inequalities:

This small disturbance assumption ...