Numerical investigation of the position effect on a hybrid wind turbine model: Integrating vertical axis wind turbines around a horizontal axis wind turbine tower

A numerical investigation is conducted on a novel hybrid wind turbine model, integrating VAWTs around a HAWT tower to enhance the overall power of HAWT. The performance of a single VAWT placed around an offshore HAWT tower is evaluated, at various position (0 degrees,45 degrees,60 degrees,90 degrees) to determine the optimal position of VAWT for maximizing power output. The study maintains a constant gap of 5.4 m from the center of tower to the middle of turbine, with constant wind velocity of 8 m/s. A three-dimensional simulation is performed to assess the aerodynamic effect of accelerated flow and high velocity created by the tower on VAWTs power performance, and compared these results to those obtained without the HAWT tower. The results indicate that the tower structure creates regions of high wind speed and stagnation regions. VAWT power output is enhanced in the high-speed regions, while power output decreases in front of the tower due to stagnation effects. At 0 degrees, the power coefficient is at a minimum of 0.0837, lower than that of turbines without the tower. At 60 degrees and 90 degrees, the coefficients improve to 0.4864 and 0.5487, respectively. Additionally, integrating small turbines on both sides at the 90 degrees position increases HAWT power by 0.83 %.