Computational fluid dynamics prediction of the reacting flowfield inside a subscale scramjet combustor
A three-dimensional, Reynolds-averaged Navier-Stokes computational fluid dynamics (CFD) code has been used to calculate the reacting flowfield inside a hydrogen-fueled subscale scramjet combustor. Pilot fuel was injected transversely upstream of the combustor, and the primary fuel was injected transversely downstream of a backward facing step. A finite-rate combustion model with two-step kinetics was used. The CFD code used the explicit MacCormack algorithm with point implicit treatment of the chemistry source terms. Turbulent mixing of the jets with the airstream was simulated by a simple mixing length scheme, whereas near-wall turbulence was accounted for by the Baldwin-Lomax model. Computed results were compared with experimental wall pressure measurements.
In this paper, the authors identify the scalability bottlenecks of an unstructured grid CFD code (PETSc-FUN3D) by studying the impact of several algorithmic and architectural parameters and by examining different programming models. The authors discuss the basic performance characteristics of this PDE code with the help of simple performance models developed in their earlier work, presenting primarily experimental results. In addition to achieving good per-processor performance (which has been addressed in the cited work and without which scalability claims are suspect) they strive to improve the implementation and convergence scalability of PETSc-FUN3D on thousands of processors.