Numerical simulation of multiple turbulent supersonic underexpanded jet

In this paper, the quadruple supersonic turbulent underexpanded jets are numerically simulated. The main goal of the presented research is to provide the numerical simulation for multiple turbulent supersonic underexpanded jets considering their interaction. A mesh of the numerical model consists of 10 million cells providing good modeling of expansion waves, shock wave such as the incident shock, reflected shock, and slip stream line in the supersonic jets. Numerical simulation is based on the three-dimensional Reynolds equations with SST k-? turbulence model being the two- equation eddy-viscosity model. The use of a  formulation for the inner parts of the boundary layer makes the model directly usable all the way down to the wall through the viscous sub-layer, hence the SST  model can be used as a Low-Re turbulence model without any extra damping functions. The SST formulation also switches to a  behaviour in the free- stream and thereby avoids the common  problem that the model is too sensitive to the inlet free-stream turbulence properties. Three dimensional compressible Reynolds equations are solved using finite volume method with the Godunov-type TVD scheme of the second order in space discretization. In calculation varied pressure ratio n = p_c/p_b, where p_c is the static pressure at the nozzle exit and p_b is the ambient pressure. It is shown that the incident shock has regular reflection from an axis of a block jet for pressure ratio n=1.45. For n=1.2 the incident shock cant pass through the slip stream line. In process of further increase pressure ratio n incident shock has irregular reflection and a strong shock forms around the centerline (Mach disc). Downstream of the Mach disc the flow becomes subsonic and the pressure and density is raised up. Conclusion The complex flow structure of multiple supersonic turbulent jet is simulated numerically; The formation and structure of multiple supersonicturbulent jets is investigated; Influence of the pressure ratio of multiple turbulent supersonic jets is shown (both regular and irregular reflection); The applied method can be recommended for the development of space-rocket technic.