Unstructured/Structured Overset Grid Simulation for the Third AIAA Sonic Boom Prediction Workshop

Abstract

The Third AIAA Sonic Boom Prediction Workshop was held in January 2020, and in the near-field section of the workshop, several simulated near-field pressure signatures of the C608 airplane, an early version of the NASA X-59, were compared. The authors have applied the unstructured/structured overset grid method to the C608 airplane case. In this method, an unstructured grid is used in the vicinity of the airplane, and the flowfield at several body lengths away from the airplane is simulated by oversetting a structured Mach cone aligned grid with the unstructured grid. It is found that the near-field pressure signatures can be obtained accurately with sharp pressure jumps in the signature by using a fine structured grid in the midfield even when a relatively coarse unstructured grid is used in the near-field of the airplane. The results show that the unstructured/structured overset grid method is a way to obtain accurate near-field pressure signatures for sonic boom estimation efficiently.