Research On Interference Between The Flow In Complex Terrain Wind Farm And Wind Turbine Wakes

In micrositting of a wind farm,wind resources of the wind farm should be calculated firstly.Then,wind turbines are placed according to the wind resources.The flow condition of complex terrain is more complicated.As the size of the wind turbine becomes larger and larger,the interference of the wind turbine to the surrounding flow on local terrain is becoming more and more obvious.Accurate analysis of wind turbine wake characteristics is very important for the reasonable arrangement of wind turbine.Currently,the micrositting of the complex terrain wind farms only considers the influence of the terrain on the wind speed of the wind turbine,without considering the interference between the surrounding flow on the terrain and the wind turbine's wake.In this paper,the interference between a 2MW wind turbine and investigate hilly terrain,one of typical complex terrains,are investigated.It includes different heights of single hill,continuous double hills,and hilly terrain with valleys.Firstly,the effects of hill height/width ratios,height of two hills and the depth of valleys on surrounding flow were studied,as well as the wake flow of wind turbine on flat terrain.Then,the wind turbine were placed in different locations,on the top of the hill,upstream and downstream of the hill.The mutual interference of wind turbine flow around,the development of the wind turbine wake and speed the recovery process were investigated.The simulation results show that the high width of the hill has great influence on the interference of the terrain flow and wake flow.When the wind turbine is on the top or downstream of the hill,if the hill is high,the hill will cause the flow separation of the lee side of the hill,and the downstream velocity recovery zone will be extended.The closer the wind turbine is to the hill,the closer is the separation point to the top of the hill.When the wind turbine is located upstream of the hill,it will also cause the flow separation of the hill lee side from a certain distance to the hill.There will be mutual influence between the two hills,which will decrease the wind speed on the hilltop to some extent.Based on simplified terrain verification,three-dimensional numerical simulations of the real complicated terrain and wind turbine wake flow were carried out.The distribution of the flow field of the real isolated hill and the continuous hills are analyzed,as well as the vortex of the flow separation and the recovery of the speed.The interaction between the real terrain and the wind turbine wakes were presented.There are interactions between two hills,and there is flow separation between two hills.The existence of the valley will increase the separation scale of the leeward hills.Therefore,in the micro-site selection of complex terrains,not only the terrain,prevailing wind direction and wind turbine wake are considered,but also the interaction of terrain flow and wind turbine wake is considered.The simulation results of this paper provide some guidance for the micrositing of actual engineering...