考虑到非线性的自由液面边界条件，用下潜涡环栅格法求解水翼绕流问题。
The nonlinear free surface boundary condition is considered and the hydrodynamics forces of the hydrofoil near the free surface are calculated by the submerged vortex lattice method.
结果表明：由于粘性的存在，使得涡环与自由表面的相互作用与无粘情形相比有许多不同。
The results show that the interaction between a viscous vortex ring and a free surface is different from the inviscid one.
将艇体看作回转体，在轴线上分布离散的点源模拟艇体，用升力面理论的涡环栅格法模拟附体；
The hull is defined as a revolution body. The hull volume effects are represented by a series of point source and sinks distributed on the hull axis.
通过模型旋翼试验得到了合理的直升机涡环边界判据，并由此计算得到了直升机通用涡环状态边界。
A reasonable criterion of vortex ring state boundary for helicopter is acquired based on model rotor tests.
研究结果表明：湍流椭圆自由射流的最显著特征是椭圆涡环的间歇产生、脱落，这些涡环一旦产生立即脱落。
The results show that the most significant feature of turbulent free jet is the intermittently generation, shed of elliptic vortex rings, and once they generate they shed immediately.
针对直升机特有的涡环飞行状态，根据直升机空气动力学理论，分析了直升机涡环状态飞行事故的现象及成因。
To investigate helicopter vortex-ring state, the phenomenon and reason of helicopter vortex-ring state flight accident is analyzed from the view of helicopter aerodynamics.
物理上看，在一个特定的临界行波速下会形成自发的周期性分离再附流，每个波谷的分离区捕获一个稳定的涡环。
Physically, at a special critical wave speed the flow may have a naturally periodical separated-reattached pattern, with each wave trough capturing a stable vortex ring.
导出了二维浅水流动的涡动方程与速度环量的随体导数表达式，以此为基础，分析了二维浅水流动中旋涡的动力学性质；
The vorticity equation was first established and the characteristics of vortex motion in two-dimensional shallow-water flows was analyzed, and then discrete vortex method (DVM) was briefly described.
环隙切剖面上形成的涡，其内部流体都要与涡外部的流体进行质量交换。
The vortices that are formed on the tangential section, there existed mass transfer between inner and outer parts of fluid.
水轮机在偏离最优工况运行时，水流的环量会使尾水管中心产生低压并形成涡带。
In case of the turbine is operated departing the optimum condition, the low presure and the vortex band will be established in the draft tube centre by the flow circulation.
通过对浮环减薄前后实验结果的对比分析，研究了浮环厚度变化对浮环轴承涡动及稳定性的影响，并给出了三维谱图、涡动比与转速图、典型分岔图。
Based on two experiments on floating ring bearing before and after floating ring thickness reduction, the effect of thickness variation of floating ring on whirl and stability was studied.
通过对浮环减薄前后实验结果的对比分析，研究了浮环厚度变化对浮环轴承涡动及稳定性的影响，并给出了三维谱图、涡动比与转速图、典型分岔图。
Based on two experiments on floating ring bearing before and after floating ring thickness reduction, the effect of thickness variation of floating ring on whirl and stability was studied.
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