A Method for Determining Two Dimensional Wall Interference on an Airfoil from Measured Pressure Distributions Near the Walls and on the Model

摘要

A measured boundary condition method in which the wall boundary condition is expressed in terms of the difference between the total measured horizontal perturbation velocity component and the hypothetical model induced one is presented. The boundary contour, C, consists of the horizontal lines, distinct from the inside of the test section walls, connected by two vertical legs, at upstream and downstream infinity. The boundary value problem is solved by a singularity distribution method. In order to ensure a unique solution, C = zero. There are always collocation points at X = zero and (x) = L, where X is the test section coordinate parallel to main flow direction, and L is the semilength of the central part of C. Tests with a supercritical airfoil throughout the entire Mach range show the method performs well, but can be improved by reducing uncertainties such as tunnel calibration and side wall effects.