Two dimensional direct numerical simulation of nonreacting confined supersonic mixing layer

Direct Numerical Simulation (DNS) results are presented for high speed nonr eacting mixing layer in a confined test section. The hypervelocity mixing l ayer experiment of Erdos ct al with H-2/N-2 stream is simulating by discret izing two dimensional Navier Stokes equation using a higher order (fourth o rder spatial and second order temporal) compact numerical algorithm. A favo urable comparison of the computation with experimentally measured wall stat ic pressure forms the basis of further analysis. Instantaneous flow picture and the mean profiles of various flow variables were examined to determine the development and general characteristics of the confined mixing layer, it has been found that the growth of the mixing layer is towards the high s peed side of the layer. Various turbulence quantities were derived From the stored time series data of the DNS calculation and the results were compar ed with the experimental results of supersonic free shear. layer as no expe rimental results of turbulence statistics are available for the confined hy pervelocity mixing layer. The increasing Reynolds stress data with the flow direction indicate that the turbulence is sustained by transferring the en ergy from the mean flow to the fluctuating field as the shear layer develop s. Although the Reynolds stress is negligible in the most portion of the wa ll boundary layers, effect of counter gradient effect is observed in the fa r downstream location of the lower wall boundary layer. The general conclus ion that for the supersonic mixing layer, various turbulence quantities lik e Reynolds stress, turbulence intensities (both streamwise and transverse) decrease with the increase in the convective Mach number is also confirmed by our results.