基于协同流壁面射流模拟带倾角下击暴流方法研究  

Method for Simulating Inclined Downbursts Based on Co-Flow Wall Jets

作　　者：何伟[1] 张宇[1] 刘千权 HE Wei;ZHANG Yu;LIU Qianquan(Faculty of Mechanical and Electrical Engineering,Kunming University of Technology,Kunming 650500,China)

机构地区：[1]昆明理工大学机电工程学院,云南昆明650500

出　　处：《防灾减灾工程学报》2025年第2期416-426,共11页Journal of Disaster Prevention and Mitigation Engineering

基　　金：国家自然科学基金项目(51168020)资助。

摘　　要：考虑下击暴流研究主要基于冲击射流模型,但对射流倾角的研究有限,且缩尺比较小不利于下击暴流风场特性研究。为此首先基于计算流体力学研究了带倾角冲击射流的风场特性,得到了倾角对下击暴流出流段的风速衰减系数表达式,然后针对壁面射流可得到大尺度下击暴流出流段风场,但忽略了倾角对风速衰减的影响,因此引入协同流以减小射流周围黏性阻力,并采用烟迹风洞试验和计算流体力学方法,得到了协同流对风速衰减的系数表达式,最后分析了壁面射流模拟下击暴流倾角致效应的可行性。结果表明:①带倾角冲击射流风场呈三维非对称特性,前侧最大水平风速的衰减速率随倾角增大而变缓,风剖面半高水平风速在倾角为30°时增幅达77.8%;②烟迹风洞试验和数值模拟结果表明壁面射流风场与下击暴流前侧出流段相似,引入协同流能够有效减缓水平风速的衰减速率;③通过建立协同流致风速衰减系数和倾角致风速衰减系数的对应关系,可实现采用壁面射流模拟任意倾角下的下击暴流平均风剖面,为模拟大尺度的带倾角下击暴流提供了新的方式。Current studies on downbursts mainly employ impinging jet models.However,research on jet inclination angles remains limited,and small scaling ratios hinder investigations of downburst wind field characteristics.To address this,the study first investigated the wind field characteristics of inclined impinging jets using computational fluid dynamics(CFD),deriving an expression for the wind speed attenuation coefficient in the outflow region under different inclination angles.Subsequently,wall jets were used to simulate large-scale outflow wind fields in downbursts,but the effect of inclination angles on speed attenuation was neglected.Therefore,co-flow was in-troduced to mitigate viscous resistance around the jet.Smoke-wire wind tunnel tests and CFD methods were employed,yielding an expression for the co-flow-induced attenuation coefficient.Finally,the feasibility of simulating inclination-induced effects in downbursts using wall jets was evaluated.The results showed that:(1)the inclined impinging jet exhibited three-dimensional asymmetry.The atten-uation rate of the maximum horizontal wind speed on the front side decreased with increasing inclination angle,while the half-height wind speed in the wind profile increased by 77.8% at 30°inclination angle.(2)Smoke-wire wind tunnel tests and numerical simulations confirmed that wall jet wind fields resembled the frontside outflow section of downbursts,and the incorporation of co-flow effectively reduced the attenuation rate of horizontal wind speed.(3)By establishing a correlation between co-flow-induced and inclination-induced wind speed attenuation coefficients,it was feasible to simulate average wind profiles of downbursts at any inclination angle using wall jets,providing a novel approach for simulating largescale downbursts with inclination angles.

关 键 词：下击暴流 冲击射流 壁面射流 倾角 协同流 大尺度 

分 类 号：TU312.1[建筑科学—结构工程] X43[环境科学与工程—灾害防治]