Numerical analysis validating the standard k-epsilon model for the kinetic energy of turbulence subjected to weak but long-lasting wind tunnel blockage acceleration

抄録

The aim of this study is to investigate the effect of weak but prolonged mean flow accelerations, such as those observed in wind tunnel blockage acceleration, on free-stream turbulence. Specifically, this research aims to validate a model previously developed based on the k-epsilon model. To test this model, the study focuses on scenarios where the turbulence under acceleration is steady and isotropic, since the model suggests that this type of acceleration has no effect on the turbulent kinetic energy. To examine this suggestion, the turbulence within a periodic box was analyzed using large-eddy simulation (LES) based on the conventional Smagorinsky model framework. The numerical analysis is based on a method that conserves velocity fluctuation intensities. The results show that while high rate of acceleration deviates turbulent kinetic energy, low rate acceleration has hardly any effect on turbulent kinetic energy, enstrophy, pressure fluctuation, relative pressure fluctuation intensity, and higher-order statistics of a velocity fluctuation. These results validate the accuracy of the model proposed in the previous studies. These results were obtained by focusing on differences in Reynolds numbers and the spatial scale of the forcing.