Large Eddy Simulations of Side Flow past a Generic Model of a High-Speed-Train using a Finite Volume and a Lattice Boltzmann Method

Abstract

Large Eddy simulations (LES) of the flow around a simplified model of the concept high-speed Next Generation Train (NGT) of the DLR are performed with a lattice Boltzmann method (LBM) and a second order accurate finite volume method (FVM). The objective is to identify and compare the performance of both approaches with respect of the prediction of cross wind effects. In order to access the accuracy of both methods, simulations of the flow around a sphere are performed for Re = 10^4 prior to the LES of the flow around the generic NGT train with a yaw angle of 30° and a Reynolds number of Re = 2.1 x 10^5. For all considered flow cases, the results are analysed with respect to instantaneous flow fields and the induced aerodynamic. The comparison reveals that the computational requirements for the LES with the LBM are lower while the LES with the FVM is more accurate in predicting the aerodynamic forces.