An efficient and accurate DSRFG method via nonuniform energy spectra discretization

An appropriate set-up of inflow boundary conditions is crucial for accurate prediction of wind effects on the target structures using Large Eddy Simulation (LES). The discretizing and synthesizing random flow generation (DSRFG) method is a commonly used method which however requires considerable computational cost. This paper attempts to improve the efficiency and accuracy of the DSRFG method by modifying the way of discretizing the energy spectra. Since the DSRFG method is originated from the Kraichnan's method, the grid effects on both methods are analyzed theoretically and examined numerically. Research results show that the Kraichnan's method is sensitive to the grid effects while the improved DSRFG method is slightly affected. Additionally, the improved DSRFG method is applied to simulate the wind effects on a low-rise building by LES and the results agree well with the NIST aerodynamic database.