| The accurate sites and the optimal layout of wind turbine in wind farms have a important role to enhance the work piece ratio.The information of joint distribution of wind speed and direction of construction site is one of major elements of selecting wind field.The distance between wind turbines is a important factor about the optimal layout of wind turbines.In another words,wake effect’s influence on wind turbines will be down with a reasonable distance,and the generating efficiency of wind turbines will be improved.Therefore,it is of great significance to study the distribution characteristics of wind speed and direction in construction site and to analyze the force,deformation and vibration patterns of wind turbine under the action of fluid by using fluid-structure coupling method.The main contents and conclusions are as follows:（1）To discover the mathematical law of the joint probability distribution of wind speed and direction,the study investigates the wind speed and direction based on the daily record data during the past 37 years in a concentrated wind field area of northwest China.Firstly,the three common extreme distribution functions are used to estimate parameters of the wind speed,and a selected Gumbel distribution is the better model closest to the actual wind speed distribution by comparing the correlation coefficient.Then,the fitting parameter results of a joint probability distribution model that is established based on the multiplication theorem and harmonic function is compared with the estimated results of another distribution model that uses the finite mixed distribution function and the genetic algorithm to get the optimum distribution model.Finally,the optimum joint distribution model predicted the extreme wind speeds in 50-year recurrence period.The results show that the fitting effect of the model based on multiplication theorem is better than the model of using finite mixture distribution method.It is necessary to consider the influence of wind direction on extremum of wind speed in solving the problems of wind farm location and fan layout.（2）In order to study the wake flow field distribution of a wind turbine,CFD numerical simulation method is used to simulate the flow field distribution of a2MW horizontal axis wind turbine.Firstly,fluid computational domain is established and meshed;Then the boundary conditions and solver parameters are set;Finally,the calculation domain is solved,and the steady-state calculation will be convergent when the residual error is less than10-3and the curve of the monitored quantity tends to be flat.The results show that the velocity decreases when the fluid flows through the wind turbine,and then with the increasing of the downstream distance,the wake velocity gradually returns to the initial velocity.（3）The fluid-structure coupling method is applied to analyze the force and deformation of a wind turbine and downstream wind turbine in tandem in different working conditions in order to study the structural response of wind turbine under wind load.Firstly,solid domain IS established and meshed.Then,the aerodynamic force calculated in the above fluid domain is transmitted to the structure through the interface surface.Finally,the solid domain is solved.The results show that when a single wind turbine works under rated working conditions,the displacement from blade root to blade tip gradually increases,and the displacement from tower bottom to tower top gradually increases.The larger blade stress area is concentrated in the middle and upper part of the blade,and the larger stress area of the tower body is concentrated in the bottom and top of the tower body.Except for a few working conditions,the law of structural response of wind turbine under other working conditions is nearly the same as that under rated working conditions.The only difference is the difference of numerical values. |
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