Optimisation of straight plate upstream deflector for the performance enhancement of vertical axis wind turbine at low, medium and high regimes of tip speed ratios.

Location and geometry optimisations of Straight Plate Upstream Deflector (SPUD) for performance enhancement of a three-straightbladed Vertical Axis Wind Turbine (VAWT) are carried out at three regimes of tip speed ratios (TSRs). Results analysis reveals that SPUD location has significant effect on the power coefficient (C_p) increment of VAWT. Placing two SPUDs both upward and downward in upstream of VAWT can achieve the highest C_p improvement at all regimes of TSRs. Overall, placing SPUD in upstream of VAWT can improve the C_p value at all regimes of TSRs, but the percentage of improvement can vary. The largest C_p improvement of 126.7% is achieved at low regime of TSRs, while at the medium and high regimes of TSRs, C_p improvements decrease to 52.7% and 52.5%, respectively. Increasing the width of SPUD can increase the average VAWT C_p improvement by 2.83% at all regimes of TSRs. [ABSTRACT FROM AUTHOR]