An Experimental Study of the Effect of Grid Turbulence on Shear Layer Evolution

Abstract

An experiment was performed in a shear layer water tunnel to determine the effect that grid turbulence, introduced within the meeting of the two streams, had on the evolution of a free shear layer. DPIV results show that the presence of grid turbulence inhibited the growth of the large coherent structures formed in the undisturbed shear layer, and thus led to an alteration of the entrainment process of free stream fluid into the shear layer. This caused more symmetry and various growth rates in the shear layer evolution. Also, the peak Reynolds stress magnitudes increased with the presence of grid turbulence.