Body force modelling of internal geometry for jet noise prediction

Abstract

The noise produced by aeroengines is a critical topic in engine design. Large-Eddy Simulation (LES) and hybrid Reynolds-Averaged Navier-Stokes (RANS)-LES provides amethod to increase understanding of influences on the noise produced and could lead to improved models for use in design. Use of Immersed Boundary (IB) and Body Force Methods (BFM) allows arbitrary geometry to be added rapidly and so this is explored to model internal geometry effects on jet noise. This reduces grid complexity and broadens the accessible design space by reducing setup time and computational cost. Using LES and BFM/IB, many effects that are difficult to test experimentally can be assessed numerically within useful timeframes. To enable challenging targets for jet noise to be met, the importance of the many influences on jet noise must be understood. These include the use of, single or dual stream jet nozzles, the presence (or lack of) of a pylon, wing, flap and deflection angles, nozzle serrations, eccentricity, temperature and velocity ratio, flight stream and upstream/internal geometry effects. The latter effects are the main focus of this study.