Simulation and visualisation of supersonic underexpanded jet interaction with a blunt body and periodic energy input

The unsteady flow structure evolution during an interaction of supersonic under expanded jet, a blunt body and periodic energy input has been investigated using the free boundary method on multilevel Cartesian grids with local adaptation based on the wavelet analysis. The grid is restructured according to the various occurring discontinuities. Periodic energy input first leads to an increase in body drag (due to energy source shockwave reaching the body) then to decrease to a level lower than if no energy input was present. A large amount of discontinuities and their interaction with each other can be observed. Due to the flow around the body being non-uniform (presence of under expanded jet and low-pressure chamber), shock waves occurring from energy input become curved. Shock waves from previous energy inputs interact with those from the next ones and contact discontinuities, which results in structures similar to the Richtmyer-Meshkov instability. The flow dynamics are illustrated with a series of images and animations which show the distribution of density and pressure, stream lines and mesh structure. © 2021 National Research Nuclear University. All rights reserved.