Numerical Investigation of Supersonic Turbulent Flow Over Open Cavities

TL;DR

This paper numerically investigates supersonic turbulent flow over open cavities, validating results against experimental data, analyzing Mach number effects, and proposing geometric modifications to enhance aerodynamic performance.

Contribution

It introduces specific cavity geometry modifications, slanted edges and smoothened corners, that significantly improve pressure and acoustic performance in supersonic turbulent flows.

Findings

Modified cavities show better pressure distribution.

Sound pressure levels are reduced with modifications.

Flow structures are affected by Mach number and geometry.

Abstract

The study of cavity flow is one of the most important research topics of unsteady aerodynamics. Supersonic turbulent flows over a cavity are mostly encountered in missiles, turbomachinery, and high-speed aircraft. The turbulence inside the cavity gives rise to excess drag, acoustic waves, pressure fluctuations, and vibrations which may lead to numerous problems like excess fuel consumption, failure of missile trajectory or mechanical parts, and aerodynamic heating. We conduct numerical simulations to investigate the flow and compare our results to existing experimental data to show quantitative validation. We then investigate the effect of the Mach number of the turbulent supersonic flow on the pressure contours and the vortical structures inside the cavity and the subsequent effect on other flow parameters like acoustic waves. Thereafter, we propose two modifications of the cavity geometry, a) slanted edges and b) smoothened corners with slanted edges, to improve the aerodynamic performance. ANSYS ICEM tool has been used for the fine mesh generation of our cavity geometry and all the simulation was run on ANSYS fluent software. The K omega SST turbulence model was used for the simulation as it can capture the near wall property with reasonable accuracy and a grid independence study was carried out to find the correct solution of the Navier Stokes equation was proceeding by the solver. The parameters like pressure contours, streamline pattern, coefficient of pressure distribution and sound pressure level (SPL) has been found and compared for both modified and unmodified open cavity at different Mach number. The modifications suggested show a significant improvement over the open cavity designs in the mean pressure distribution and sound pressure level distributions.