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High-order numerical methods and CPU/GPU performance portability of simulation software

MEGEP (Mécanique, Energétique, Génie civil & Procédés)

Lien Youtube: https://youtube.com/live/E3qn5ynxmSY?feature=share

High-fidelity computational fluid dynamics (CFD) solvers require a lot of compute power, and must be able to exploit efficiently massively parallel high-performance computing (HPC) systems. With the fast-paced evolution of HPC hardware and in particular the shift towards GPU-accelerated systems, these solvers and their underlying algorithms must constantly be maintained and improved to remain in line with the current technological landscape. In this context, developing and maintaining solvers portable across all the available HPC architectures without compromising performance has become a significant challenge. This thesis focuses on discontinuous high-order methods and investigates how modern sowftare techniques and libraries can be used to develop performance portable solvers in a sustainable way. For this purpose, a new Spectral Difference (SD) solver for the Navier-Stokes equations has been developed from scratch and the different implementation strategies selected are discussed. The resulting software is benchmarked across various HPC architectures, and an in-depth analysis of its performance, portability and scalability is proposed. The use of hp-adaptation is also explored as a means to better focus the compute power on the regions of interest, and thus reduce computational cost. Finally, the diffusive extension of the SD method is revisited and an alternative approach providing better numerical stability and allowing for more efficient implementation strategies is considered.

Jury

M. Guillaume HOUZEAUX	Barcelona Supercomputing Center	Reviewer
M. Vincent MOUREAU	CORIA	Reviewer
Mme Susanne CLAUS	ONERA	Examiner
M. Bruno DESPRES	Sorbonne Université	Examiner
M. Pascal TREMBLIN	CEA Paris-Saclay	Examiner
M. Guillaume DAVILLER	CERFACS / INP Toulouse	Thesis supervisor
M. Gabriel STAFFELBACH	ONERA	Invited
M. Pierre KESTENER	CEA DAM DIF	Invited