能质扩散尾流模型的数值研究

Numerical Study on the Kinetomass Diffusive Wake Model

本文提出一种适用于复杂地形风电场微观选址的风力机尾流模型。研究从湍流平均运动的动能方程出发,通过对非线性项中的速度进行线性化,同时引入能质的概念,得到尾流衰减对应的能质密度满足的对流扩散方程;采用粒子随机运动求解方程得到能质密度,并通过变换将动能衰减叠加到原平均动能场中,得到对应的尾流速度。研究表明,基于能质扩散的风力机尾流模型在平坦地形上与实验数据吻合得较好;对于复杂地形情况,模型通过边界条件将地形信息与浓度方程相耦合,所得尾流速度随着地形起伏而发生变化,且计算量适中,可用于预测复杂地形风电场的流场。

In this paper, a turbine wake model which can be used in the micro-siting problem over complex terrain is developed. Based on the turbulence average kinetic energy equation, the convection-diffusion equation that the kinetomass satisfies is obtained by linearizing the velocity in the nonlinear term and introducing the concept of kinetomass. Kinetomass is obtained through solving the equation by particle randomly walking method. Then add the kinetic deficit to the average kinetic energy, the wake velocity is obtained. The results show that the proposed wake model is in good agreement with the experimental data on flat terrain. For complex terrain, the model contains the terrain information through the boundary condition of the concentration equation. The wake velocity can change according to the shape of the ground. Besides, the total computation is acceptable. Therefore, the proposed wake model can be applied to calculate the flow field over complex terrain.