The Impact Of Roughness Elements On The Formation And Development Of The Atmospheric Surface Layer In Wind Tunnel

The simulation of atmospheric surface layer in wind tunnel was an important basic work of wind engineering research.With the application and development of wind tunnel simulation,it becomes increasingly important to simulate the characteristics of atmospheric surface layer.In this paper,the atmospheric surface layer in wind tunnel was studied.The numerical simulation method and experiment method were used to study the parameters of the roughness elements which affected the formation and development of the atmospheric surface layer in wind tunnel.The measuring point model location and aerodynamic roughness change in the law with the parameters of roughness elements were acquired.The wind tunnel experiment and numerical simulation results were compared under the same laying of the roughness elements conditions.It showed that the numerical simulation results were in good agreement with experimental.The main conclusions of this paper were as follows:when the other laying conditions of roughness elements were certain,Aerodynamics roughness and the measuring point position defers to exponential function relations change,and the measuring point influences on atmospheric surface layer thickness was small.The position of import rough elements did not affect the parameters of atmosphere surface layer.When the laying density of roughness elements S was＜6.5K,the coefficients A, B in exponential function,as well as the atmosphere surface layer thickness,changed with the laws of logarithm;when the laying density of roughness elements S was≥ 6.5K,the coefficients A,B in exponential function,as well as the atmosphere surface layer thickness changed with the law of linearity.The change of roughness elements length didn't affect aerodynamic roughness of the experimental zone on the model.The coefficients A,B of the exponential function didn't change with the laying length of the roughness elements,and the atmospheric surface layer thickness increased linearly.The coefficients A,B of exponential function to the height of roughness elements met the changes of linearity,atmospheric surface layer thickness with the height of roughness elements was in the logarithmic laws.When the height of roughness elements K＞0.055m,continuing to increase the height of roughness elements didn't change the atmosphere surface thickness due to the top wall in the wind tunnel.