Evaluating the Performance of Two Marine Hydrokinetic Turbines in a Tandem-Array Configuration

Abstract:

This laboratory study centers on the interaction of two model marine hydrokinetic devices arranged in a stream-wise tandem configuration. The goal is to determine the effect of an upstream turbine on the performance of the downstream turbine. Specifically, this study focuses on the changes in power generation that occur as the stream-wise spacing between devices is varied. Understanding the interaction between laboratory scaled marine hydrokinetic devices is a necessary step prior to field deployment. This study analyzes multiple aspects of the research problem to provide a global overview on the interaction between two devices. Testing was conducted in the hydraulic flume facility (9.8 m long, 1.2 m wide and 0.4 m deep) at Bucknell University. The devices were two-bladed model marine turbines with a rotor diameter of 0.1 m. Tests were performed for a fixed range of separation distances between the two devices. For each separation distance, thrust and generated power of both devices was measured. Moreover, the velocity profile and turbulence intensity incident on the downstream device was determined for each case. Results demonstrated that the performance of a downstream device was affected by the presence of the upstream turbine. The evolution of the wake velocity was strongly related to the power generation levels of the downstream marine hydrokinetic device. Results depicted that an ideal separation distance exists between devices such that the power generation and performance of the downstream marine hydrokinetic device are maximized.