Modeling dynamic stall of a straight blade vertical axis wind turbine

Abstract

This paper investigates the development of the dynamic stall of a full straight blade vertical axis wind turbine (SB-VAWT) using computational fluid dynamic modeling for solving the 2D Navier–Stokes equations. The 2D unsteady Navier–Stokes equations are solved with the concept of Reynolds averaging. A mesh independency test is analyzed using the General Richardson Extrapolation technique. Two turbulence models are applied, namely the SST k−ω and the Transition SST models. It has been found that the stall development is extremely sensitive to the transitional modeling and small laminar separation bubbles will only be accurately predicted by accounting for the transition. However, the transition affects the overall turbine performance by up to 20% and delays the peak of the predicted torque by about 11°, and therefore it is crucial to include laminar-turbulence transition in the design and optimization process of SB-VAWTs.