OPTIMIZATION OF SD8020 FOIL OSCILLATING MOTION FOR PROPULSION
The thrust producing performance and efficiency of an SD8020 foil oscillating motion was studied and optimized through force and torque measurement and dye flow visualization, in the water tunnel at low Reynolds number of 13,000-16,000. The foil was set into pitching and heaving motion under different oscillation patterns to mimick the flapping and swimming motion of the marine creatures. The force and moment data associated with the each motion (pitching and heaving) were collected and used as optimization basis for best flapping motion combination. The propulsive efficiency and thrust coefficient of the pitching foil were determined as a function of the Strouhal number, pitch amplitude and angular frequency. A propulsive efficiency of 30% was obtained experimentally at low Strouhal numbers. The flow visualization has revealed different wake patterns at various Strouhal numbers and can be classified into three regimes – a drag wake, a transition wake and a thrust wake. Based on the force and efficiency data collected for the pure pitching motion, increasing pitch amplitude and angular frequency was associated with a decrease in propulsive efficiency and an increase in thrust forces produced. A high efficiency value of 0.3, accompanied by a thrust coefficient of order one is found at a low pitch amplitude of 10°, angular frequency of 0.79 rad/s and Strouhal number of 0.05. This presented the best conditions for thrust production observed at low Strouhal and Reynolds numbers.
W.S.Chai S.Srigrarom
School of Mechanical and Aerospace Engineering Nanyang Technological University, Singapore, 639798, SINGAPORE
国际会议
北京
英文
1-4
2008-10-23（万方平台首次上网日期，不代表论文的发表时间）