Improvement of Fast Simulation Method of the Flow Field in Vertical-Axis Wind Turbine Wind Farms and Consideration of the Effects of Turbine Selection Order

To determine the optimal arrangement of vertical-axis wind turbines (VAWTs) within wind farms, we previously developed a technique (method-1) that constructs a flow field based on two-dimensional (2D) velocity data derived from computational fluid dynamics (CFD) simulations. In this study, we introduce an improved approach (method-2), which follows the same fundamental concept as method-1 but incorporates a more efficient algorithm for generating the flow field. Comparative analyses confirmed that method-2 produces results equivalent to those of method-1 while significantly reducing computational time and cost. Method-2 reduces the computation time of method-1 by approximately 50% for parallel layouts (θ = 0°) and up to 60% for slanted layouts (θ = ±45°). Using method-2, we further investigated the performance of a wind farm composed of eight VAWT rotors arranged in a linear configuration under the assumption of a 2D flow. The results highlighted two important aspects. First, the predicted power output is unaffected by the order in which the flow fields are superimposed during calculation; second, the method exhibits high sensitivity to even small variations in rotor placement within the layout when the spacings between rotors are short. Additionally, we examined how rotor spacing affects the distribution of power generation across the rotor array. These findings of this study validate the efficiency of method-2 and offer practical insights for designing optimized VAWT layouts.