13:45 GPU and multi-core accelerated simulations of bluff body flows using  vortex methods – D. Rossinelli (ETHZ)

We present a full on-GPU solver and a multi-core/GPU-assisted solver for simulating bluff body flows using a remeshed vortex particle method. The efficiency of the method relies on fast and accurate particle-grid interpolations on GPUs for the remeshing of the particles and the computation of the field operators. The GPU implementation uses hardware framebuffer operations to perform efficient particle-grid operations and a CUFFT-based solver for the Poisson Equation with unbounded boundary conditions.
The accuracy and performance of  the full on-GPU simulations and their relative advantages/drawbacks over CPU based computations are reported  in simulations of flows past an impulsively started  circular cylinder from Reynolds numbers between 40 and 9,500. The results indicate up to two orders of magnitude speed up of the GPU implementation over the respective CPU implementations. The accuracy of the GPU computations depends on the Re number of the flow. For Re up to 1000 there is little difference between GPU and CPU calculations but this agreement deteriorates (albeit remaining to within 5% in drag calculations) for higher Re numbers as  the single precision of the GPU adversely affects the accuracy of the simulations.