Numerical simulation of spatial wind fields in Xumishan Grottoes over complex terrain

Windy weather frequently occurs in Northwest China, and wind erosion is a typical issue for stone carvings in the caves. In the present study, computational fluid dynamics (CFD) simulations relying on steady 3D Reynolds-averaged Navier-Stokes (RANS) equations were used to simulate the spatial wind field over complex terrain with field measurement validation. This study has the following two aims: (1) to evaluate the accuracy of wind fields simulations with the Interpolated Multiscale Profile (IMP) method over complex terrain; and (2) to provide spatial wind field data of Xumishan Grotto Zone under neutrally stratified atmospheric boundary layer (ABL) over complex terrain. Unmanned aerial vehicle (UAV) oblique photogrammetry and multirotor UAV technology provide application scenarios for the establishment of a high-precision digital model and the determination of accurate inlet boundary conditions. By compiling user-defined functions (UDF) and using the block interpolation method, this method addresses the overestimation of the inlet wind velocity caused by the large elevation difference of the inlet over complex terrain. The results show that the 3D steady RANS simulation based on the IMP method can reasonably and accurately simulate spatial wind fields over complex terrain. This study also provides spatial wind fields data for addressing stone carving erosion caused by strong winds in semi-open Grottoes.