This work investigates high‐order central compact methods for simulating turbulent supersonic flows that include shock waves. Several different types of previously proposed characteristic filters, including total variation diminishing, monotone upstream‐centered scheme for conservation laws, and weighted essentially non‐oscillatory filters, are investigated in this study. Similar to the traditional shock capturing schemes, these filters can eliminate the numerical instability caused by large gradients in flow fields, but they also improve efficiency compared with classical shock‐capturing schemes. Adding the nonlinear dissipation part of a classical shock‐capturing scheme to a central scheme makes the method suitable for incorporation into any existing central‐based high‐order subsonic code. The amount of numerical dissipation to add is sensed by means of the artificial compression method switch. In order to improve the performance of the characteristic filters, we propose a hybrid approach to minimize the dissipation added by the characteristic filter. Through several numerical experiments (including a shock/density wave interaction, a shock/vortex interaction, and a shock/mixing layer interaction) we show that our hybrid approach works better than the original method, and can be used for future turbulent flow simulations that include shocks. Copyright © 2009 John Wiley & Sons, Ltd.

The farfield noise generated by supersonic jets is investigated by a computational aeroacoustics methodology that couples 3-D large-eddy simulation (LES) near field data with the Ffowcs Williams-Hawkings method for farfield noise prediction. In order to accurately simulate jets at off-design supersonic conditions, we employ LES with characteristic filters for shock-capturing. This approach limits the dissipation of noise-producing turbulent fluctuations, and is suitable for incorporation into existing solvers. To further limit dissipation, a shock detector is used to determine shock locations and characteristic filters are applied locally. In this study, both perfectly-expanded and under-expanded unheated jets are investigated, with and without using characteristic filters. Comparisons with similar numerical and experimental data show reasonable agreement of the jet mean flow, turbulent statistics, and acoustics results. Preliminary grid-refinement shows improvement in these results.

In this paper, we explore the use of a second-order unstructured-grid, finite-volume code for direct noise prediction. We consider a Mach 1.5 jet impinging on a perpendicular flat plate. Hybrid LES-RANS simulations are used to calculate directly both the flow field and the radiated sound. The ANSYS Fluent commercial code is utilized for the calculations. The acoustic field is obtained directly from the simulations and is compared with the integral approach of Ffowcs-Williams–Hawkings. Results indicate the existence of a preferred radiation angle. The spectrum obtained is in good agreement with observations. This points out to the possibility of handling the effects of complicated geometries on noise radiation by using unstructured second-order codes.