Assessment of an improved Random Flow Generation method to predict unsteady wind pressures on an isolated building using Large-Eddy Simulation

A wide variety of improved or modified Random Flow Generation (RFG) methods have recently been proposed for simulating the Atmospheric Boundary Layer (ABL) in a Large-Eddy Simulation (LES) framework. A distinct advantage of RFG methods over precursor-successor methods is the significant savings that can be made in terms of setup and computational costs. A review of the literature indicates that RFG methods are mostly evaluated in terms of velocity statistics and spectra. However, many applications in computational wind engineering ultimately aim to simulate the wind loads acting on a building. It would therefore be useful to evaluate the real capabilities of RFG methods for predicting unsteady wind pressures acting on various shapes of building. In this paper, one of the available RFG methods based on a summation of Fourier harmonic functions is assessed for various shapes of isolated building (a full-scale cube, a wind-tunnel cube, a high-rise building and a low-rise building) in terms of pressure statistics and spectra. Comparisons between measurements and simulations show that the RFG method tested here could be particularly relevant for industrial applications, provided that the inlet turbulence intensity profile is adapted.