基于分离涡方法的定日镜风效应研究

选用RANS湍流模型、大涡模拟与分离涡模型等计算流体动力学(CFD)方法,应用由新的湍流脉动流场产生方法DSRFG(discretizing and synthesizing random flow generation)模拟风场实际的湍流边界条件,对定日镜结构的风压分布及流场进行分析。将数值模拟结果与风洞试验数据进行对比,给出风向角为0°工况下定日镜结构的风压系数分布规律及特点,分析5种模型下定日镜周围的流场分布和涡量分布。结果表明,RANS模型虽然能够模拟出结构周围流场的基本规律,但却无法模拟出风场中的紊流和涡旋的分离扩散情况。大涡模拟及分离涡模型对风场中的紊流和涡旋的分离扩散有较好的模拟效果,在风压系数的分布上也与风洞试验数据拟合较好。在定日镜周围流场中脉动风压系数的分布上,分离涡模型的模拟结果较大涡模拟更为接近风洞试验值,且耗时更少。

RESEARCH ON WIND EFFECT FOR DETACHED EDDY SIMULATION OF HELIOSTAT

Heliostats is a typical structure affected by wind loads In this paper,a new approach to generate turbulence called Discretizing and Synthesizing Random Flow Generation(DSRFG) is used to simulation the turbulent boundary conditions,the techniques of Computational Fluid Dynamics(CFD),such as Reynolds Averaged Navier–Stokes Equations(RANS)Model,Large Eddy Simulation(LES)and Detached eddy simulation(DES),were adopted in this study to predict wind loads on and wind flows around the heliostats. The computed results were compared with extensive experimental data which were obtained at wind tunnels,the wind loads distribution of heliostats for wind direction 0° are predicted,the velocity and vorticity distribution around the heliostats were analyzed with 5 kinds of techniques. The results indicatesd that the RANS model can`t give satisfactory predictions for the tribulent flow or vortex in the wind field. The LES and DES model can yield encouraging results in the predictions of the separation and diffusion of vortices,while LES and DES with simular result to the data of wind tunnel test. It was found through the comparison that the vortex simulation result around the heliostats of DES is closer to the wind tunnel test value than that of LES,and DES has the advantage of providing rapid solutions.