Experimental analysis of combusting flows developing over a plane-symmetric expansion

An experimental study of inert and combusting flows developing over a plane -symmetric expansion is presented. The Row under investigation consists of two fully developed turbulent channel Rows of air (inert flows) or air plus propane (combusting flows) that are emerging just ahead of the sudden expa nsion. Such a flow geometry has been chosen to test turbulent combustion mo dels that are able to take into account either a variable-mixture compositi on or (and) the simultaneous presence of large-scale coherent structures an d stochastic turbulence. The present study concerns cases for which both st reams have the same mass flow rate and the same equivalence ratio, The resu lts put into evidence the asymmetry of the inert mean velocity field. The m ost striking effect of the presence of combustion is the symmetry brought t o the mean flowfield and the related statistics accompanied by a determinis tic pulsation of the reacting zones whose amplitude is governed by the char acteristics of the reactants streams, Such a dramatic change in the flow pr operties represents a great challenge as far as computations of these flows are concerned.