Unstructured, High-Order Scheme Module with Low Dissipation Flux Difference Splitting for Noise Prediction

Thorough understanding of aircraft airframe and engine noise mechanisms and the subsequent acoustic propagation to the farfield is necessary to develop and evaluate noise mitigation concepts. Therefore, continued assessment and development of advanced prediction methodologies and tools is essential. Despite significant progress made in computational fluid dynamics (CFD) in past several decades, some production unstructured CFD codes used at NASA for noise prediction are only 2nd order accurate at best. In this SBIR study, we propose to develop a modular high-order scheme with low dissipation flux difference splitting that can be integrated into existing CFD codes for use in improving the solution accuracy and to enable better prediction of complex physics and noise mechanisms and propagation. The salient features of our proposed approach include: (1) high-resolution schemes with physics-based low-dissipation flux-difference splitting; (2) very low memory requirements; and (3) modular structure for easy integration into existing CFD codes. During Phase I, a module providing 3rd order accurate schemes will be developed and integrated into FUN3D code. Verification and validation studies will be conducted to demonstrate the improved solution accuracy. During Phase II, 4th order accurate schemes will be developed and implemented with FUN3D, and the performance of improved schemes will be assessed for realistic aeroacoustic problems. Adaptive use of high-order schemes near solution discontinuities (such as shocks) will be investigated. Phase II plans will also consider integration of the high-order module with other unstructured CFD codes such as USM3D and Loci/CHEM.