CFD simulation of snow transport over flat, uniformly rough, open terrain: Impact of physical and computational parameters

Abstract

In the past, Computational fluid dynamics (CFD) simulations have been successfully applied for the prediction of snow drift around buildings and on building roofs. A literature study indicates that a wide range of influential computational and physical parameters exist for snow drifting predictions in CFD, while the impact of these parameters is unclear, resulting in a lack of available CFD simulation guidelines. Therefore, this study presents a systematic and generic analysis with emphasis on the fundamentals of snow transport prediction techniques. Snow transport over flat, uniformly rough, open terrain, including snow saltation and snow suspension is successfully simulated using CFD and the results are compared to field measurements of snow concentrations for validation. This paper investigates the impact of grid resolution, falling velocity of snow, turbulent Schmidt number, threshold friction velocity of snow and turbulence model on the CFD simulation results. The results show that the falling velocity and the turbulent Schmidt number have largest impact. A slight change in the falling velocity or the turbulent Schmidt number significantly impacts the predicted snow concentration in the air. In addition, the turbulence model mainly affect the turbulent kinetic energy, another key factor that influences the numerical predictions of snow transport.

LES over RANS in building simulation for outdoor and indoor applications: A foregone conclusion?

“…Many studies have shown the large impact of the choice of Sc t on the resulting concentration fields (e.g. Tominaga and Stathopoulos 2007Gousseau et al 2011a;Blocken et al 2016a;Toja-Silva et al 2017;Li et al 2018;Kang et al 2018). Second-order closure is also possible for the turbulent heat and mass fluxes, but this option is not often used in CFD for building simulation.…”

Wind speed acceleration around a single low solid roughness in atmospheric boundary layer

“…S2. Because the height of simulation domain is only 10 m (much smaller than the thickness of atmospheric boundary layer 41 ), the shear speed at upper boundary is set to be u * (the same value at inlet) as previous study did 46 . Consequently, turbulent kinetic energy and turbulent dissipation rate wouldn’t change along the length of upper boundary 47 .…”

DriftScalarDyFoam: An OpenFOAM-Based Multistage Solver for Drifting Snow and Its Distribution Around Buildings

“…The snow transport in a suspension layer is calculated by using a convection-diffusion equation (Tominaga et al, 2011a;Zhou et al, 2016a;Zhu et al, 2017;Kang et al, 2018), in which the snow phase is considered to have the same velocity as the airflow in the horizontal direction, and a virtual velocity in the direction of gravity is added to the convection term to represent the falling of snow. The complete equation is expressed as…”