Numerical study of the interaction between closely placed multiple drag-type vertical-axis wind turbines

Abstract

In this study, we investigate the flows around two Savonius turbines that rotate independently by numerical simulation considering the application to ocean current pawer generation. In general, when analyzing the flow around a rotating object, a rotational coordinate system is often used. However, it is difficult to calculate with such coordinate system when two objects rotate independently. Therefore, we use the overset grid that consists of two rotational coordinates for each turbine immersed in a steady coordinate to calculate this turbines’ system. In this study, two-dimensional simulation is performed for two turbines rotating opposite direction, by changing various parameters such as the shape of the blades of the wind turbines, the direction of the mainstream, so that the effect on the dynamic characteristics of the wind turbine was investigated. The results show that regardless of the mainstream direction, the torque coefficient tends to increase as the blade aspect ratio increases, while the torque coefficient tends to decrease as the blade width is reduced.