Meshing remains somewhat of an art. Engineers tend to spend a significant amount of time generating grids, while mathematicians develop more advanced algorithms that may end up being exercised on meshes inappropriate for a given application. A mesh that provides a suitable solution for one flow condition can be shown to be inadequate at a different flow condition.
The optimal grid is different for different Reynolds and Mach numbers. Users of the same flow solver may even get slightly conflicting results if they distribute points differently.
Creating proper meshes for a given problem typically requires some iteration and experience. AIAA sponsored workshops povide an avenue whereby feedback from subject matter experts can be gathered and techniques for meshing domain-specific problems can be evaluated.
The 4th AIAA Propulsion Aerodynamics Workshop (PAW04) was held during the weekend of 7-8 July 2018 and preceded the 54thAIAA/SAE/ASEE Joint Propulsion Conference at the Duke Energy Convention Center in Cincinnati, OH. The two-day workshop provided participants an impartial forum to present numerical results for three separate challenging validation benchmark cases. Of interest to the propulsion community were cases simulating unsteady and steady-state aerodynamics of complex inlet and nozzle exhaust flows. There were 35 participants in attendance with several others who submitted data. During workshops, participants are encouraged to exchange ideas and evaluate the effectiveness of existing computational fluid dynamics (CFD) codes and modeling strategies.

Fig. 1: A centerline cut through a multi-block structured mesh for the 4th Propulsion Aerodynamics Workshop baseline test case.
A set of workshop-supplied grids are published by the workshop’s organizing technical committee for each test case. Participants are encouraged to use these meshes in order to help reduce scatter in results that are contributed and to help encourage participation. For the latest workshop, in addition to the previous one, the workshop-supplied meshes for two of the three test cases were created using Pointwise.
Over the course of the past few Propulsion Aerodynamics Workshops, a number of meshing best-practices have been developed. To learn more about the latest workshop and discover what we have learned about meshing these types of challenging internal flow problems over the years, follow the link below.