MODELLING OF SHOCKWAVE IN CONVERGING-DIVERGING NOZZLE USING SHOCK CAPTURING METHOD

The fonnation of shock has always seen as undesirable occurrence. The knowledge
about its fonnation is critical especially during design stage. Highly accurate
numerical model are needed in order to accurately simulate fonnation of shock. One
case study on supersonic flow separation has been selected as basis. Grid
independent study is done to study the effect of grid density as well as refinement
direction (axial, radial, and both axial and radial) to the accuracy of the solution. It is
also desirable to investigate the fonnation of shocks under different nozzle operating
pressures. The simulation is using several nozzle pressure ratios (NPRs) as
manipulated parameters. Simulation results show that refinement in radial direction
gives the optimum trend followiog data while refmement in both axial and radial
gives quite accurate data but not followiog the experimental data trend. Higher
density mesh is found to be capable of capturing weak shocks and shock-boundary
layer interaction. Lastly, under different operating pressure, it is found that shocks
location is closer to the throat as the nozzle pressure ratio is decreased.

Keywords: Shock Wave, Flow Separation, Nozzle Pressure Ratio. Grid Refinement