Numerical study on moving downburst with inclusion of the environmental wind.

Thunderstorm downbursts can impose critical wind loads on long-span transmission line structural system. Existing research has predominantly focused on stationary downbursts, with limited attention given to the analysis of travelling downbursts influenced by environmental wind and parent cloud motion. This paper utilizes the impinging jet method to simulate a travelling downburst at a small Reynolds number, employing the Delayed Detached Eddy Simulation turbulence model for solving the wall-bounded turbulent flow. The radial wind speed distribution of the travelling downburst is subsequently validated against previous experimental, numerical, and observational data. A comparative study is then conducted to discern the differences in the radial wind speed distribution between stationary and travelling downbursts. Finally, a parametric study investigates the influence of jet inlet speed, environmental wind and parent cloud motion on the maximum radial wind speed distribution of the travelling downburst. The findings reveal a significant disparity in the radial wind speed distribution between stationary and travelling downbursts. Notably, parent cloud motion, environmental wind, or their combined effects can alter the height providing the maximum radial wind speed. This variation has implications for the wind load distribution of travelling downburst across the conductor span of the transmission line structural system. [ABSTRACT FROM AUTHOR]