Comparing methods for reducing artificial pressure fluctuations using large eddy simulation in high-rise building wind load assessment

Reducing artificial pressure fluctuations (RAPF) is one of the key challenges in simulating atmospheric boundary layer turbulence. This study, based on the synthetic turbulence method, compares the performance of three RAPF methods: inlet mass correction (IMC), divergence-free correction (DFC), and local pressure correction (LPC). First, large eddy simulations of an empty domain show that the IMC and DFC methods effectively suppress unrealistic pressure fluctuations throughout the flow field. As the turbulence develops downstream, the pressure fluctuations decay rapidly and become almost insignificant. Conversely, the LPC method only reduces local nonphysical pressure fluctuations by adjusting the pressure reference location, but as the distance from the reference point increases, the pressure fluctuations gradually increase. Moreover, the IMC and DFC methods adjust the initial turbulent field to meet inlet mass balance or divergence-free conditions, which results in changes to the initial turbulence characteristics. However, the LPC method avoids modifying the initial turbulence, allowing it to better maintain the original turbulence properties. Finally, the simulations for wind loads on the high-rise building indicate that the application of the IMC, DFC, and LPC methods results in reasonable mean, standard deviation and peak values of pressures on the building surfaces, as well as accurate calculations of the integrated base forces and moments.