NUMERICAL MODELLING FOR STUDIES ON SUPERSONIC FLOW OVER A CAVITY WITH SPOILER INVOLVING VELOCITY FIELD AND OVERALL SOUND PRESSURE LEVEL BY LES-APPROACH

Abstract

The present investigation pertains to the development of an appropriate numerical model for the supersonic flow over a 3D cavity with a length-to-depth ratio of 2. The Mach number of the supersonic free-stream is 2 in addition the Reynolds number of the flow is 105. The numerical simulations have been conducted by means of Large Eddy Simulation (LES) method. The Smagorinky model is introduced for this research. The numerical predictions have been expressed in the form of velocity vector as well as overall sound pressure level along the side wall of the open cavity. As witnessed, the velocity vector superbly describes the flow behaviour inside the cavity. Very large recirculation is also noticed inside the cavity without spoiler. Nevertheless, the reduction of the recirculation inside the cavity is realized by introducing a spoiler in the form of one-fourth of a cylinder at the leading edge of the open cavity. With the introduction of the spoiler, the overall sound pressure level along the side wall of the cavity is also decreased to certain level. Correspondingly, the sound pressure levels get decreased by almost 14 dB and 12 dB at both front and aft walls of the cavity, respectively. The alterations in the flow characteristics of the cavity along with the spoiler is also examined. In general, the comparisons between the simulation predictions of the cavity flows with and without the use of the spoiler is also made