| Nowadays,the shortage of non-renewable energy is becoming more and more serious,and the development of clean energy has become crucial.With the rapid development of wind energy,the construction scale of wind farms is gradually increasing.Although wind power brought many positive effects to our lives,t he internal balance of the atmospheric boundary layer will be disturbed during the operation of wind turbines.Therefore,it is very important to study the impact of wind farm operation on the atmospheric boundary layer.This paper took the NREL 5 MW wind turbine as the research object,based on the OpenFOAM open source software,simplifies the physical wind turbine blades through the actuation line model,and combines the large eddy simulation and the relevant theories of the atmospheric boundary layer to analyze the uniform inflow and shear inflow of a single wind turbine.Numerical simulations of wind turbines and different wind turbines were carried out to study the impact of their operation on the atmospheric boundary layer.It was found that under uniform inflow,the speed distribution of a single wind turbine and the upstream hub height of a wind turbine with tandem,staggered,and different hub heights all showed a regular shape,that is,the center speed was higher,and the speed on both sides was lower.There was still a loss of speed at the height of the downstream hub,which would result in a low aerosol diffusion rate in the atmospheric boundary layer,which would directly affect the emissivity of the cloud layer,and affect the ambient temperature and rainfall.In order to further study the disturbance of the atmospheric boundary layer during the operation of the wind turbine,this paper used the Q criterion to identify the wake vortex structure of the wind turbine under uniform inflow.It was found that the upstream wind turbine would have stable tip vortices,attached vortices,and blades root vortex.As the mixing effect of the tip vortex and the root vortex increases,the wake vortex at the downstream of the wind turbine gradually was decomposed into broken vortices.By comparing the wake vortex structures downstream of three different wind turbines,it was found that the downstream wake vortices of the staggered wind turbines were the most intense and had the greatest impact on the height of th e atmospheric boundary layer and the turbulence energy.In order to make the flow field closer to the atmospheric environment,this paper adopts the shear inflow boundary condition.In the shear inflow,the operation of a single wind turbine and wind turbine will affect the vertical velocity in the flow field.Increase the height of the atmospheric boundary layer,which would affect the surrounding air quality.When a single wind turbine was operating under different wind shear indexes,the wind turbine with a small shear index would produce less velocity disturbances on the flow field than that of a large shear index,and in the flow field with a small shear index Medium,the speed loss recovers quickly.That is to say,the impact of wind opportunities in different terrains on the atmospheric boundary layer was different.In the shear inflow,rectangular wind farms,yaw rectangular wind farms,and staggered wind farms have different effects on the atmospheric boundary layer.Staggered wind farms have the gre atest impact,followed by rectangular wind farms,and yaw rectangular wind farms have the least impact.At the same time,the downstream wake vortex disturbance of the staggered wind farm was also the most severe. |
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