Shockwave and Mach Disk Comparison in Convergent and Convergent-Divergent Nozzles by analyzing CFD plots

A shock wave is a special kind of wave referred to as a steep, finite pressure wave. The change in the flow properties across such a wave are abrupt, in some situations, shocks are undesirable because they interfere with the normal flow behavior. Shock waves cause energy losses in relation to their intensity. At even higher pressure ratios, a Mach disc which is a straight shock front in the center of the jet with specifically high losses is formed [1]. Mach disk is a shock wave that is perpendicular to the direction of the flow which is called a normal shock wave. A normal shock can be seen when the flow turns parallel to the centerline. This normal shock creates a Mach disk in the exhaust flow. The compression waves force the flow to turn back inward and increase in pressure. If the compression waves are strong enough, they will merge into an oblique shock wave and form a new Mach disk [2] In the present investigation, an attempt was made to analyze and compare shockwave and Mach disk for Convergent nozzle (C nozzle) and Convergent- Divergent nozzle (CD nozzle) by considering the various CFD (Computational Fluid Dynamics) plots such as pressure plots and velocity vector plots. The pressure plot shows the pressure variation and the velocity vector plot shows presence of shockwaves across the nozzle. Fluent Software has been used for modeling, computation, simulation and to obtain the plots.