Computational load imbalance due to direct integration of chemical kinetics is a well-known performance issue in parallel reacting flow simulations  . We introduce an open-source dynamic load balancing model  to address this problem within OpenFOAM, an open-source C++ library for Computational Fluid Dynamics (CFD). Due to the commonly applied operator splitting practice in reactive flow solvers, chemistry can be treated as an independent stiff ordinary differential equation (ODE) system within each computational cell. As a result of  highly non-linear characteristics of chemical kinetics, a large variation in  convergence rates of  ODE integrator may occur, leading to a high load imbalance across multiprocessor configurations. However, the independent nature of chemistry ODE systems leads to a problem that can be parallelized easily ( also termed embarrassingly parallel in the literature) during the flow solution. The presented model takes advantage of this feature and balances the chemistry load across available resources. When the load balancing is utilized together with a reference mapping model also introduced in this paper , a speed-up by a factor of 10 is reported for practical reactive flow simulations . To the best of our knowledge, this model is the first open-source implementation of chemistry load balancing in the literature.
Computational load imbalance is a well-known performance issue in multiprocessor reacting flow simulations utilizing directly integrated chemical kinetics . We introduce an open-source dynamic load balancing model named DLBFoam to address this issue within OpenFOAM, an open-source C++ library for Computational Fluid Dynamics (CFD). Due to the commonly applied operator splitting practice in reactive flow solvers, chemistry can be treated as an independent stiff ordinary differential equation (ODE) system within each computational cell. As a result of the highly non-linear characteristics of chemical kinetics, a large variation in the convergence rates of the ODE integrator may occur, leading to a high load imbalance across multiprocessor configurations. However, the independent nature of chemistry ODE systems leads to a problem that can be parallelized easily ( called an embarrassingly parallel problem in the literature) during the flow solution. The presented model takes advantage of this feature and balances the chemistry load across available resources. Additionally, a reference mapping model is utilized to further speed-up the simulations. When DLBFoam it utilized with both these features enabled , a speed-up by a factor of 10 is reported for reactive flow benchmark cases . To the best of our knowledge, this model is the first open-source implementation of chemistry load balancing in the literature.
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due to direct integration of chemical kinetics
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parallel
multiprocessor
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utilizing directly integrated chemical kinetics
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named DLBFoam
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problem
issue
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the
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the
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the
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also termed embarrassingly parallel
called an embarrassingly parallel problem
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When the load balancing is utilized together with
Additionally,
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also introduced in this paper
is utilized to further speed-up the simulations. When DLBFoam it utilized with both these features enabled
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practical reactive flow simulations
reactive flow benchmark cases