The Experiment About Groin Flow Structure And The Application Research Of Wall Function In Turbulence Model

The wall fuction is an important auxiliary equation for turbulence model simulating the flow field,effects of the precise simulating extent on flow field,velocity,turbulent kinetic energy distribution and so on.Especially for the high R_e turbulence model as two-dimensionalκ-εmodel.In the low R_e region near the wall,using suitable wall fucion can save memory and computing time,simulate the real flow better.Nowrdays,it is too many wall fuction are used inκ-εmodel, which type of wall function could simulate a better turbulence charactrestics is unknow,and the compare among the wall fuctions has not been researched,too.In this paper,firstly,the physical model experiment of groin's flow structure has been researched;then,usingκ-εturbulence model to numerical simulate the groin's flow sructure experiment,there are three type of wall fuctions been used in the simulation;and the zero equation model is also used to simulate groin's flow sructure.Finally,the calculation results have been compared to the experiment data indeep,and found a better wall function.The main conclusions and innowative points are follows:(1) Besiders being a comparsion basis for the numerical model,the physical model experiment also can improve the hydraulic properties of groyne..It have been done the flat-bottom and scour hole two condition tests,and the turbulent motion measure were emphsis on the groin head and backflow region where are turbulence foucs region,and anslysised the law of turbulence characteristics,compared the flatbottom and scour hole two condition then getting the scouring and silting balance mechanism.(2) Using the zero equation model and theκ-εtubulence model,which contain three types of wall fuction,to numerical simulate the grion's flow structure, the numerical results are compared to the measured results.And the compare shows that the numerical results ofκ-εtubulence model are better than the zero equation model;and in theκ-εtubulence models,the law of logarithm wall function is better than the other two froms.(3) At last,applicating GuNiuSha reach in the middle reaches of the yangtze river as an example,using theκ-εtubulence model with the lagarithm wall function and fitted-body coordinate to calculate,the calculation results and measured value are close.The relevant conclusions of this paper can provide some reference for the selsction and improvement of the wall funtion in theκ-εtubulence model.