Analysis of Shock-Wave Structures in a Supersonic Biplane by Focusing Schlieren Technique

Abstract

The flow field in a three dimensional biplane model is investigated by using a focusing schlieren method which can visualize a density gradient of arbitrary cross sections along a light path. Experiments were conducted in the 60mm×60mm indraft supersonic wind tunnel at the Institute of Fluid Science, Tohoku University at M_∞ = 1.7. Two test models were used in this experiment: the two-dimensional and three-dimensional models. First of all, the performance of the focusing schlieren system was evaluated by using the two dimensional model. The flow visualization in the three dimensional model is conducted by using the conventional schlieren method and more detail flow visualization by using the focusing schlieren method. Additionally, surface pressure distribution is measured by using the pressure-sensitive paint (PSP). From combined measurements, the flow field in the three dimensional model was discussed. It was found that shock wave structures in the test model vary in the span direction. Additionally, the cause of high pressure regions on the wing surface was understood by comparing with the PSP result.