ANALISIS ALIRAN FLUIDA PENGARUH VARIASI JARAK DAN DIAMETER SILINDER SIRKULAR PADA SISI ADVANCING BLADE TERHADAP PERFORMA TURBIN AIR SAVONIUS TIPE MYRING n=1.
Savonius water turbines are vertical type turbines that can be used in low water flow velocity conditions because it have high initial torque. This turbine is suitable to be applied in rivers and sea in Indonesia because it can receive water flows from all directions. The results from previous studies show the rotor with myring n=1 blade type has the highest power coefficient, which is 10.98% higher than conventional Savonius turbines. In a following study a modification was made by adding a circular cylinder on the advancing blade side make an increase of maximum CP(Power Coefficient) of 18.04% with the number of TSR is 0.7, so turbine efficiency increased. In this study, numerical analysis was carried out by modifying the Savonius water turbine with myring blade n=1 type. This research using gambit for making geometry model(preprocessing) and applying the numerical simulation method using 2D analysis of Computational Fluid Dynamics (CFD) using ANSYS 17.0-Fluent for solution and postprocessing. Numerical analysis is done by adding variations of the circular cylinder, so the flow velocity of the fluid going to the advancing blade side is high, and it can increase the turbine performance. The ratio between the diameter of the circular cylinder and the diameter of the turbine blade (ds / D) varies by 0.2, 0.3 and, 0.4 and the placement of the circular cylinder with a horizontal distance (X/D) by 0.5, 1, and, 1.5. Variation of Savonius water turbine with ds/D 0.4 and X/D distance ratio 0.5 with TSR number 1 have the highest performance increase which is increased by 37.38.