TY  - JOUR
AB  - Purpose– Prompted by the empirical evidence that achievable flow solver speeds for large problems are limited by what appears to be a time of the order of O(0.1) sec/timestep regardless of the number of cores used, the purpose of this paper is to identify why this phenomenon occurs. Design/methodology/approach– A series of timing studies, as well as in-depth analysis of memory and inter-processors transfer requirements were carried out for a typical field solver. The results were analyzed and compared to the expected performance. Findings– The analysis shows that at present flow speeds per core are already limited by the achievable transfer rate to RAM. For smaller domains/larger number of processors, the limiting speed of CFD solvers is given by the MPI communication network. Research limitations/implications– This implies that at present, there is a “limiting useful size” for domains, and that there is a lower limit for the time it takes to update a flowfield. Practical implications– For practical calculations this implies that the time required for running large-scale problems will not decrease markedly once these applications migrate to machines with hundreds of thousands of cores. Originality/value– This is the first time such a finding has been reported in this context.
VL  - 24
IS  - 7
SN  - 0961-5539
DO  - 10.1108/HFF-01-2013-0016
UR  - https://doi.org/10.1108/HFF-01-2013-0016
AU  - Löhner Rainald
AU  - D. Baum Joseph
PY  - 2014
Y1  - 2014/01/01
TI  - On maximum achievable speeds for field solvers
T2  - International Journal of Numerical Methods for Heat & Fluid Flow
PB  - Emerald Group Publishing Limited
SP  - 1537
EP  - 1544
Y2  - 2024/09/22
ER  -