Improved Simulation of Internal and External Hypersonic Flows using High-Order Implicit Shock Tracki
Abstract
Research Problem: Understanding and predicting hypersonic flow is crucial to design and control vehicles that operate at extremely h,igh speeds, e.g., those used for atmospheric re-entry, responsive space access, and prompt global strike. Computational fluid dynami,cs (CFD) has become an invaluable tool to gain fundamental insight into flow physics and facilitate the prediction and control of co,mplex flows; however, hypersonic flows present unique challenges for modern CFD methods due to the strong shocks and complex flow fe,atures, e.g., shock/shock and shock/boundary layer interaction. Highly refined hexahedral grids aligned with shocks and boundary lay,ers (BLs) and finely tuned numerical dissipation are required to obtain accurate aerothermodynamic and unstart predictions. As a res,ult, the overall hypersonics simulation workflow, particularly me, substantial expertise. This makes parametric flow studies and design optimization a significant challenge and severely limits the c,omputational hypersonics (CH) workforce. Thus, there is a significant and immediate need for novel, innovative approaches to CH to a,ddress these challenges so that hypersonic flows can accurately and reliably be predicted. This is the gap this project aims to addr,ess.Objectives: I aim to improve the state-of-the-art in hypersonic flow simulation technology by developing and maturing a novel nu,merical method with high accuracy per degree of freedom (DoF) and automated grid alignment with shocks and BLs to mitigate the hyper,-sensitivity of hypersonic flow predictions to the grid and numerical dissipation. I will use the method to conduct an automated par,ametric study of hypersonic flow over a model vehicle with deployed control surface (sliced cone-flap) at various angles of attack a,nd flap angles, where the interaction of shocks and BLs is crucial to obtain accurate predictions.Technical Approach: I propose a fu, these features using high-order methods and optimization. My group has pioneered such a method that simultaneously computes the flo,w solution and implicitly aligns the grid with shock waves and contact discontinuities by solving an optimization problem (does not,explicitly generate a mesh that conforms to the shock surface). We have shown it is able to accurately resolve two- and three-dimens,ional high-speed, inert and reacting flows on extremely coarse meshes, even when the shock surface is complex. We will extend the ap,proach to hypersonic flows by accounting for viscosity and developing iterative solvers to ensure efficient parallel performance.Out,come: A successful research campaign would improve the state-of-the-art of CH by producing a numerical method that has high accuracy, per DoF, has low numerical dissipation, and leads to accurate predictions on non-ideal grids (tetrahedral elements without pre-alig,nment to shocks and BLs). It would also produce a computational investigation into hypersonic flow over a sliced coneflap at various,ns on coarse, non-ideal grids, which will reduce the computational cost of hypersonic flow simulations, significantly reduce the bur,den of mesh generation for complex geometries, and improve overall CH workflow automation. As a result, the expertise required to co,nduct CH investigations will expand to include students and a broader group of CFD engineers, increasing the overall CH workforce. T,he proposed method is aligned with JENRE (Jet Engine Noise Reduction), a Naval Research Laboratory (NRL) software used for CH studi,es; future integration of this method into JENRE will directly impact research at NRL. APPROVED FOR PUBLIC RELEASE
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 01, 2022
- Source ID
- N000142212299
Entities
People
- Matthew Zahr
Organizations
- Office of Naval Research
- United States Navy
- University of Notre Dame