Parametrization of the cumulant lattice Boltzmann method forfourth order accurate diffusion part II: Application to flow around a sphere at drag crisis

The optimized cumulant lattice Boltzmann method with fourth order accurate diffusion is used to simulate the flow around a sphere up to Reynolds number 10(6). The drag crisis is well captured by the method. We demonstrate with our results that the drag crisis corresponds to an almost discrete jump in the flow conditions. The intermediate values of drag in a small range of Reynolds numbers around the drag crisis observed in averaged data sets are found to originate from the flow switching between the high and the low drag conditions. Around the critical Reynolds number, the time spent in the low drag condition increases with the Reynolds number such that the average drag curve has a finite steepness. (C) 2017 Elsevier Inc. All rights reserved.