Free flight measurement technique in shock tunnel

Abstract

This article contains a description of a free flight force measurement technique currently used at the ISL (French-German Institute of Research of Saint Louis) shock tunnel in order to obtain aerodynamic coefficients. The principle of the method is to let a studied model fly freely during the few milliseconds of the supersonic (or even hypersonic) flow produced by a shock tunnel. During the test time, the aerodynamic forces applying to the model are predominant compared to the gravity. The resulting motion can be recorded with one or more high speed cameras in order to be processed later. In this paper a solution using a single camera is proposed. The use of a unique camera can traditionally only allow the measurement of the in-plane displacement and rotation. A method is presented here to overcome this drawback and to get the complete 3D displacements and rotations.