Numerical Modeling and Application of Horizontal-Axis Wind Turbine Arrays in Large Wind Farms

The global supply of energy is still tight, even with the rise of renewable energy utilization and abundant wind energy. More and more large wind farms have been installed globally. As of 2020, China's total installed capacity accounted for 38.8%, far ahead of other countries. The layout of horizontal-axis wind turbine (HAWT) arrays in large wind farms poses three main issues: (1) How to select a site. (2) How to arrange the HAWT arrays to achieve greater power extraction at a specific wind farm. (3) How to reduce the noise generated by HAWTs. The numerical simulation of a HAWT wake field generally includes the analytical method (AM), vortex-lattice or vortex particle method (VM), panel method (PM), blade element momentum method (BEM), generalized actuator method (GAM), and direct modeling method (DM). Considering the computational cost, this paper combines DMs and mainly adopts the BEM-CFD coupling method, including uniform and non-uniform loading of axial force. Forty specially designed numerical experiments were carried out, which show that: (1) the BEM-CFD method greatly improves the calculation speed within the accuracy range of a thrust coefficient less than 2.5%, making it very suitable for the calculation of large wind farm HAWT arrays; (2) for regular HAWT arrays, it is reasonable to choose a 6D spacing in the wind direction and a 4D spacing in the crosswind direction for simplicity in practice.