Multi-objective Optimization Of Wind Environment For A High-rise Residential Complex Based On Building Planning Parameters

With the rapid development of urbanization in China,all kinds of urban land are increasingly scarce.As an effective solution,high-rise residential complex has been widely promoted.The emergence of more and more high-rise residential complex has brought many wind environment problems,in which the problem of pedestrian level wind environment and natural ventilation is most closely related to daily life.Therefore,it is very important to study the mechanism and influence law of various factors on wind environment,so as to provide basis and suggestions for the planning and design of residential quarters.In this paper,the influence of planning elements on wind environment and multi-objective optimization of wind environment are studied by numerical simulation.The main work of this paper is as follows:By comparing the results of numerical simulation and wind tunnel test,the reliability of SST k-? and RNG k-? turbulence models in pedestrian level wind environment and natural ventilation is verified.It i s found that for pedestrian wind environment simulation,the results of the two turbulence models are very close to the test results in high wind speed area,and lower than the test wind speed in low wind speed area.For natural ventilation simulation,SST k-? and RNG k-?can predict the wind pressure coefficient well.Finally,through the comparative analysis of FAC2,MNMB,FGE and R four evaluation indexes,it is found that except that the FAC2 of the two models in pedestrian level wind environment simulation is the same,in other cases,each index of SST k-? is better than RNG k-?,that is to say,the comprehensive performance of SST k-? is better than RNG k-?.After verifying horizontal homogeneity and grid independence,the effects of building density,building height thickness ratio,building width thickness ratio and wind direction angle on pedestrian wind environment and natural ventilation are studied.The results show that:in general,the building density,building height thickness ratio and wind direction angle will have a significant impact on the pedestrian wind environment and natural ventilation,especially the wind direction angle.Appropriate wind direction angle can not only effectively increase the area of wind comfort zone,but also greatly improve the natural ventilation potential of downstream buildings.On the contrary,the ratio of building width to thickness has no obvious effect on pedestrian wind environment,but has little effect on natural ventilation.The order of influence degree of planning elements on pedestrian wind environment is proposed:wind direction angle>building density>building height thickness ratio>building width thickness ratio.Accordingly,the order of influence degree of planning elements on natural ventilation is proposed:wind direction angle>building density>building height thickness ratio.Based on the previous numerical simulation results,the influence of selection method,independent variable form and regression times on the regression model is analyzed,and the regression model of(?)and(?)is established.The regression model was tested for goodness of fit and significance,and compared with CFD results,the relative error between the two was less than 10%.Finally,NSGA-? algorithm and three decision methods are used to optimize the wind environment.The corresponding(?)and(?)values of the final optimization scheme are 0.68 and 0.39,and the corresponding planning parameters are ?=20%,?H=4.5,?B=1,?=10°.