Longitudinal Vortex Wind Turbine: Effect of the Blade Lengths

The longitudinal vortex wind turbine (LV-WT) is a novel propeller type, but the turbine blade is the circular cylinder. The blade is driven by lift force of the longitudinal vortex (LV). This work is to examine a simple single-cylinder blade to suppress the negative driving-force portion by cutting and keeping only the useful area. Unsteady Reynolds-Averaged Navier-Stokes (URANS) simulation is used for investigation. For the original single blade, the positive driving force was generated around the dominance of the LV at the crossing section. Meanwhile, the negative driving force appears far from the ring regime. When the original blade is diminished to avoid the unpleasant parts, the negative regions are suppressed completely. The distribution of the aerodynamic forces along the blade length is symmetric for the length extended equally. Final, the equally extended blade with the length of three times of the ring width is built and tested in the wind tunnel. The tendency of the experimental data and the CFD results correlate very well.