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。

youdao

The surface of propeller and its trailing vortex is divided into a number of small hyperboloidal quadrilateral panels with constant source sink and doublet distributions.

螺旋桨表面和它的尾涡面离散为四边形双曲面元，每个面元上布置等强度偶极子和源汇分布。

youdao

Moving path lines, tangential and axial average velocities of particles at the vortex surface are obtained by the photography method.

通过摄像法得出了旋涡表面流体质点的运动轨迹、切向和轴向时均速度。

youdao