Aerodynamic analysis of the large-scale V-shaped vertical axis wind turbine

The popularity of Vertical Axis Wind Turbine (VAWT) is rising for offshore wind energy generation. Novel VAWT designs, such as V-shaped VAWT (V-VAWT), are in the research phase and have potential for commercial use in the future. Large-scale VAWT can reduce the Levelized Cost of Energy (LCOE) in offshore areas because of its simplicity in design and the placement of heavy, complex mechanical components near the water surface. Considering this fact, this study evaluates the aerodynamic efficiency, defined as the effectiveness of converting wind energy into rotational mechanical energy, of a noble 2 MW V-shaped VAWT. Initially, the aerodynamic performance of a three-bladed V-VAWT is analyzed for 10 different blade models, broadly classified into constant-chord and linearly tapered-chord models. Two engineering models, Qblade and B-GO, both based on the Double Multiple Streamtube (DMST) method, are compared to determine which blade model exhibits superior aerodynamic performance. Following this, a detailed flow-field analysis is conducted using 3D Computational Fluid Dynamics (CFD) simulation of the rotor incorporating the selected blade model. Mesh, time, and rotation independence tests are performed to ensure the accuracy of the CFD solution. Finally, the results from the two analytical models and the CFD model are compared across different Tip Speed Ratios (TSR). The results indicate that the rotor achieves an average power coefficient ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>C</mml:mi> <mml:mi>P</mml:mi> </mml:msub> </mml:mrow> </mml:math> ) exceeding 0.4 at TSRs above five across all three models, confirming the high aerodynamic efficiency of the V-shaped rotor for the chosen blade configuration.