Visualization of Flow Fields by Use of a Tuft Grid Technique

Abstract

A technique for obtaining a physical picture of the flow field behind a wing, combination of wings, or other airplane components is described wherein the action of a great number of tufts of uniform length, attached to a wire grid, are photographed from far downstream. This procedure yields, with a minimum of labor, an approximate vector plot of the flow field in a plane normal to the air stream. An examination of the data obtained from an application of this tuft grid technique to the study of the flow fields behind several low aspect ratio rectangular and delta wing arrangements indicates that analyses of such factors as trailing vortex strength and location and approximate downwash and sidewash angles over a large area around lifting surfaces and other aerodynamic forms may be satisfactorily conducted by this technique.