Calculation of Two-Dimensional Flow Past Airfoils

Abstract

The classical method of calculating flows past airfoils is to assume that viscous effects are confined to their immediate neighborhood and that the remainder of the flow-field can be assumed inviscid. Hence the pressure distribution may be computed from potential-flow equations and the drag subsequently obtained from the turbulent boundary-layer equations. This procedure has a considerable range of practicability but is inappropriate for the solution of some practical problems which occur, especially at high angles of attack and with the more complicated airfoil shapes in use at the present time. At low speeds these problems are chiefly associated with separation, both for laminar and turbulent flows, and with the understanding of the correct representation of transition and turbulent flow processes. At transonic speeds the appearance of shocks in the inviscid part of the flow field and their interaction with the boundary layer represent additional difficulties.