Research Of Wind Load Characteristics On Multi-span Saddle Membrane Structure

Membrane structure is a new architectural form which is developed in the 1950 s.It’s widely used in various facilities fields.Quality light membrane structure belongs to soft type structure,the influence of wind load is very important,so in the design of membrane structure,wind load belongs to the main control load.At present,the main research method for wind load include numerical simulation,field measurement and wind tunnel test.They all have advantages and disadvantages,when we are in reaching,we can choose the appropriate method according to the actual situation and reality condition.This article adopts the numerical simulation and field measurement,to analyze the multi span saddle membrane structure which is located in Zhejiang University of technology zhaohui campus.In the first part of article,firstly,we use four turbulent model: the standard k-? model,the RNG k-? model,Realizable k-? model,and the RSM model,to analyze the multi span saddle membrane structure by numerical simulation analysis,then field measurement to the multi span saddle membrane structure,get the figure of the average wind speed in 5seconds and the figure of the the average wind pressure coefficient in 6points’ s up and down surface,and then,we compare the measured results with the numerical simulation results,to choose a turbulence model which have the closest value with the measured value,then carry out the follow-up study in the multi span saddle membrane structure with the turbulence model,and hope to provide a little reference for related research in the future.The study found that(1)In the measured instantaneous,the gap with the average wind speed and the instantaneous wind speed is big,and have strong wind characteristics.(2)In the highest angle point of the surface of membrane structure,the top surface suffer the negative pressure,the lower surface have the positive pressure,the angle point suffer the upward suction by the wind,the net wind pressure coefficient is-1.4,and in the lowest angle point have the opposite result,which suffer the downward pressure,the net wind pressure coefficient is 0.8.(3)The change trend of average wind pressure coefficient with the field measured data and the results of numerical simulation are almost the same,the results are in good agreement,verify the reliability of numerical simulation.(4)The four turbulence model all can show the tendency of wind pressure better which is in the membrane surface,the change trend of four kinds of turbulent models are similar,only have nuances on the average wind pressure coefficient values.Comparing the measured results can be seen that RNG k-? model’s simulation result is closest to the measured result.In the second part we analyze the multi span saddle membrane structureby numerical simulation analysis which is using RNG k-? model,and gain the figure of the average wind pressure coefficient about membrane structure in all kinds of different conditions in the multi span saddle membrane structure‘s top and bottom surface surface,the figure of net wind pressure coefficient and the velocity vector diagram about the flow field,in order to supply future related projects as a reference.The main conclusions in article are as follows:(1)The area which suffer extreme wind pressure in the multi span saddle surface of membrane structure are always in the corner points,the average wind pressure coefficient in membrane surface center are often have smaller absolute value.(2)The higher area in the top surface at multi span saddle membrane structure always have negative pressure,bottom surface always have the positive pressure,and the lower area have the opposite performance,which is the top surface always have the opposite performance and the bottom surface always have negative pressure,this is mean the top point in membrane structure suffer the suction of the wind,and the low point suffer the down pressure of the wind.(3)As the increase of the initial prestress at the membrane surface,the shape of the surface of membrane structure is change as well,and the initial prestress at the membrane surface does not change distributions of average wind pressure coefficient on the surface of membrane structure,also have little influence on the average wind pressure coefficient of numerical size.(4)When in the different wind angle,the average windpressure coefficient on the membrane surface have the different distribution form.(5)Rise span ratio will not change the average wind pressure coefficient’s distribution on the membrane structure,but will change its size,and the greater the rise span ratio,the greater the average wind pressure coefficient.