Simulasi Numerik Pengaruh Variasi Sudut Silinder Sirkular di Depan Returning Blade Terhadap Performa Turbin Angin Savonius Overlap

Abstract

Previous experiment has been carried out on Savonius wind turbine with additional
overlap ratio and variation of circular cylinder stagger angle to improve its performance.
However, the experiment didn’t show flow visualization around the turbine. Therefore,
numerical simulation using Computational Fluid Dynamics (CFD) method must be carried out
to validate the experiment result and obtain the best performance and flow visualization of
overlap Savonius wind turbine. The turbine simulated has an overlap ratio of 0,3. Then, the
circular cylinder is placed in front of returning blade with a distance ratio (S/d) 1.7 and
various stagger angle of 45 ?, 50 ?, 55 ? and 60 ?. The flow velocity used is 5 m/s. Turbulence
model used in this simulation is k-epsilon realizable with transient pressure based. The final
result is overlap Savonius wind turbine with circular cylinder has increased its performance of
31,56 % compared with overlap Savonius wind turbine without circular cylinder. The best
performance occurs at 55 ? circular cylinder stagger angle in front of returning blade with
0,4118 Coefficient of Power (Cp) value. The flow visualization shows that 55 ? circular cylinder
stagger angle is able to create the most optimum nozzle effect.