Lift-Induced Drag Computation by Lamb Vector Integration

Abstract

Lift induced drag is computed from flow field data by a volume integral of the Lamb vector (cross product of the vorticity and the velocity vector). While conventional far-field methods can compute profile drag by volume integral, induced drag is usually computed by Maskell’s method which requires to make a two-dimensional plane cut from threedimensional data. Utilizing the Lamb vector integration, plane data reconstruction is not necessary and an insight of the drag production can also be obtained. The acquired aerodynamic forces, such as lift induced drag and lift are evaluated in comparison with the values computed by the conventional methods. Numerical solutions of the Reynolds averaged Navier-Stokes equations are analyzed by the present method. Two test cases are discussed consisting in a two dimensional airfoil and a three dimensional elliptic wing.