LES simulations of an experimentally-produced inclined downburst: implications of a storm motion

Downburst winds produced by an isolated stationary thunderstorm create their characteristic signatures in terms of a theoretically symmetric ring vortex and strong near-surface winds. However, there is a high likelihood for the storm to be moving rather than being stationary, which in turn changes the downburst flow features. The differences are mostly pronounced in the flow asymmetry based on the direction of storm propagation, which consequently subjects structures to different velocity profiles which affect the wind loading. To further investigate the implications of the storm motion, an experimentally-produced inclined downburst caused by the moving storm was replicated numerically. In this paper, the LES simulations of the inclined downburst were performed to focus on the full-field representation of the flow in the near-surface region. The flow field was visualized in terms of velocity contours and radial velocities were compared with measured data. Overall, the LES data show a good agreement with the measured data.