Effects of changing aspect ratio through a wind-tunnel contraction

Abstract

The effects of changing aspect ratio (AR) through a wind tunnel contraction keeping all other parameters constant were studied. Four contractions were constructed and fitted to an existing wind-tunnel facility with fixed geometrical parameters. Developments of boundary layers on the walls and in the corners of contraction, and a change in corner boundary-layer flow were the main effects observed. Consideration of streamline convergence effects as well as pressure histories were required while performing comparisons of boundary layer thicknesses. A collapse of data was revealed by an examination of the mean velocity profile along the diagonal of the exit plane.