Hydrodynamic Power Optimization of a Horizontal Axis Marine Current Turbine With Lifting Line Theory

The classical lifting line optimization of a horizontal-axis turbine is described in this paper. The theory is based on the classical helical vortex model of constant pitch to determine the optimum blade circulation distribution for maximum power extraction from a fluid stream in steady flow. A vortex lattice method in combination with the induction factor method for computing the induced velocities is used to solve the optimization equations. Optimum power curves, including the effect of viscous drag are presented. The application of the theory to the determination of optimum chord and pitch distributions is illustrated in a simple design example of a marine current turbine.