High Reynolds Number Hydrokinetic Turbine Force Analysis and Test Equipment Design

Abstract

Hydrokinetic turbines have the potential to harvest large amounts of energy from the ocean’s tides but their fluid dynamics are not yet fully understood. Most laboratory facilities are unable to achieve full dynamic similarity when testing scale model turbines due to the difficulty of matching key dimensionless parameters in a wind tunnel setting. However, Princeton’s High Reynolds number Test Facility (HRTF) is unique since it is able to operate at pressures up to 220 bar, allowing for manipulation of the density of the air flowing inside the wind tunnel. The HRTF will facilitate scale model testing of hydrokinetic and wind turbines that can provide insight into the forces and moments experienced by the full scale structures. In order to achieve this goal, a testing “carriage” must first be designed that will house the turbine model inside the HRTF and contain force and torque sensors that measure the loads and moments imparted on the turbine. Selection of the proper force sensor requires an analysis of the loads experienced by a turbine under operation. The carriage design includes many other parts to be either selected and procured or manufactured. This paper outlines the theory behind the fluid dynamics of tidal turbines and describes the design process of creating a testing carriage for the HRTF. The results of preliminary data taken in an atmospheric wind tunnel test as well as the next steps for this ongoing project are also discussed.