Experimental Study of a Normal Shock/Homogeneous Turbulence Interaction
Résumé
The problem of shock wave – turbulence interaction is addressed experimentally in a simplified flow configuration: the shock is normal to the flow direction and the incoming turbulence is homogeneous and quasi-isotropic. This paper mainly deals with the problem of the experimental realization of such an interaction in a supersonic wind tunnel. On the basis of an experimental set-up that showed great aptitude in creating a shock-turbulence interaction pure from major parasitic effects, see Barre et al. (1996), a new turbulence generator and a new shock generator were designed and built. It was found that the new turbulence generator creates a homogenous and quasi-isotropic turbulent supersonic flow at a distance of about 25 mesh sizes. The benefit of this new system was to increase the turbulence level before the interaction with the shock from 0.3 % to 1.7%. The new shock generator system permitted to stabilize a normal shock of larger size compared to the previous configuration, at a distance of 32 mesh sizes. Initial conditions at the shock position were determined with details: important turbulent quantities of the supersonic flow before the interaction, such as turbulent kinetic energy, dissipation rate, Taylor micro-scale and integral length scale, were estimated. With this new experimental set-up, detailed turbulence measurements before and after the shock using fluctuations diagram techniques will be performed.
