Computational fluid dynamics analysis of mach 1.5 supersonic cavity flow by open source software and comparison of simulation results with comercial software

The focus of this research is high-speed flow over open cavities. Internal carriage of stores on aircrafts is modeled as a rectangular cavity, which is crucial from an engineering perspective, since internal carriage of bombs and stores decreases the radar signature of the aircraft and aerodynamic heating. Supersonic flow through an open cavity can cause extremely complex flow characteristics. In the cavity region, flow field is compressible, unsteady and turbulent, so it is quite important for aerospace applications to be able to predict the nature of the flow and the characteristics over time, mostly to be able to control it during flight. In this study, supersonic open cavity flow simulations are performed with commercial and open source software, separately, in order to compare the simulation results and determine the capabilities and limits of OpenFOAM for supersonic flow as an open source software. Unsteady, compressible and time dependent flow conditions are utilized. Simulation results are compared by considering sound pressure levels on cavity walls, Fast Fourier Transform (FFT) results and pressure fluctuations for the time dependent nature of the flow. The simulation results are also compared with experimental data in terms of sound pressure levels on the bottom wall of the cavity geometry. Under favour of experimental data at the bottom wall of the cavity it is possible to comment on the reliability of the data from both software. The effects of numerical scheme, time discretization, tolerance and residual restrictions on the results are investigated, as well. Three dimensional cavity geometry is also analized, in order to examine the ability of OpenFOAM in capturing the effects of the third dimension. According to simulation results, the results for supersonic flow over a rectangular cavity are closer to experimental findings with OpenFOAM when compared to commercial ANSYS-Fluent software, which makes open source codes promising for supersonic flows, although OpenFOAM requires much finer mesh structure than Fluent.