Downburst wind field characteristics under moving effect
WANG Zhisong1,2,WU Yanjun1, FANG Zhiyuan1
1.School of Civil Engineering, Chongqing University, Chongqing 400045, China;
2.Key Laboratory of New Technology for Construction of Cities in Mountain Area,Ministry of Education, Chongqing University, Chongqing 400045, China
Abstract：Downburst wind field study under steady state is relatively mature.Due to storm moving, the actual downburst wind field is unsteady.In order to study effects of jet-flow velocity and translational velocity on characteristics of downburst wind field, a test for downburst wind field under moving was conducted with an impinging jet device.The large eddy simulation（LES） was used to build 3-D reduced scale and full-scale wind fields of impinging jet at moving nozzle to do numerical analysis.The results showed that the numerical simulation results agree well with test ones; moving speed has an obvious peak amplification action, and jet velocity has little effect on peak value; the translating downburst wind field has features of wind shift and obvious asymmetry, translating speed has a significant amplification effect on the horizontal wind speed near wall ahead of storm, but it causes some reduction in wind speed behind storm; when the downburst develops to enter a steady state, the wind profile increases to the maximum firstly and then decreases rapidly with increase in its height, the maximum wind speed appears at the lower end of the wind profile; the curve peak position and the duration of the curve descending segment are related to moving velocity and jet one in a certain proportion.
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