Design of Single Component Airfoils Using an Inverse Boundary Element Method

摘要

An inverse boundary element formulation is presented for potential flow for the determination of contour coordinates of a single component airfoil from a prescribed velocity distribution. The airfoil boundary is replaced by a closed polygon consisting of straight-line elements with nodes at the end points and a linearly varying vortex density. Discretization of the stream function integral equation governing the flow around an airfoil leads to an algebraic set of equations. This is solved in an iterative manner: node coordinates are sought which satisfy the set of equations when the velocities at the nodes are prescribed. For practical calculations the computer program INVAIR is utilized. As input data for the program, a prescribed velocity distribution with corresponding angle of attack and an initial airfoil are given. The program has a routine for distribution initial nodes at equidistant values of a contour curvature function for ease of data input. The program, written in FORTRAN-20, was run on a DEC-20 computer.