This, the researchers believe, is caused by the surface of the water smoothing out a vortex of air coming off the flying fish and reducing drag.
研究者相信，这源于水面平滑了飞鱼迎面的风涡，降低了阻力。
2
As airfoil thickness is increased, the average pressure drag, affected by leading edge vortex is reduced even to be negative, and meanwhile friction has little increase.
由于前缘涡的影响，翼型厚度增加，平均压差阻力系数变小，甚至会出现负值。
3
Such parameters of flow characteristics are investigated as lift and drag coefficient and vortex shedding frequencies.