涡

The rolling-up of the leading-edge vortex sheet and interaction with the trailing-edge vortex are simulated numerically by using the two-dimensional unsteady analogue and vortex-in-cell method.

本文应用二维非定常比拟和恪子涡(Vortex-in-Cell)方法，数值模拟了三角翼前缘涡层的卷起以及与尾涡的相互作用。

Moreover, to prevent the vorticity from entering into the body, the concept of "residual vorticity" is introduced in the sense that partial circulation of the vortex sheet is remained at the boundary without being diffused into the flow field. Blobs very close to the wall are thus unnecessary.

为避免部分新涡泡太过接近边界，我们引入了「残留涡度」的概念，将离边界甚近之环量转为涡片形式留在边界上，以减少环量进入物体内部之误差。

Delta wing ; vortex method ; detached vortex ; vortex sheet.

三角翼；涡方法；脱体涡；涡层

To simulate the diffusion of the vortex sheet into the flow field as time goes on, Koumoutsakos' analytical solution is employed, in which an effective vorticity flux is derived and used for solving the vorticity diffusion equation.

而涡片之环量随时间扩散进流场之现象则藉由Koumoutsakos之理论，以边界上之等效涡度通量求解扩散方程式，得解析解后，再将之离散为边界附近之新涡泡。

To simulate the diffusion of the vortex sheet into the flow field as time goes on, Koumoutsakos' analytical solution is employed, in which an effective vorticity flux is derived and used for solving the vorticity diffusion equation. The solution is then discretized into blobs (called "-blobs") in the vicinity of the boundary.

而涡片之环量随时间扩散进流场之现象则藉由Koumoutsakos之理论，以边界上之等效涡度通量求解扩散方程式，得解析解后，再将之离散为边界附近之新涡泡。

The numerical results were in good agreement with the measured results. The experimental and numerical results show that the vortex ring was induced by baroclinic effect and Helmholtz instability in the vicinity of the thruster exit after the donation wave exhausted the tube. The intensity, shape and location of the suspended shock varied when the shape of the vortex ring changed.

爆轰波溢出爆轰管后，斜压效应和Helmholtz不稳定导致涡环的产生，同时在流场中形成止于涡环的悬吊激波，涡环形状的变化又引起悬吊激波的强度、形状和位置的变化。

The analysis shows that with given grid size higher accurate difference scheme can give higher resolutions with wider range of scales, or with given accuracy large grid size can be used for the higher accurate difference scheme. The second part is the numerical simulation of two-dimensional axisymmetric jet. The simulation results show the structure in the near field and the initial transition. In the near field, Kelvin-Helmholtz instability leads to the formation of vortex ring, and nonlinear growth leads to the merging of vortex ring. This is the main instability form. Under the assumption of axisymmetry and two-dimensional computing conditions, the results are applicable only in the near field.

第二部分采用高精度的差分格式对二维轴对称射流进行了数值模拟，模拟结果显示了射流流场结构和涡结构的发展过程，在射流流场近区，K-H失稳导致涡环的产生以及非线性效应的增长导致涡环的对并是射流失稳的主要形式；分析指出在轴对称假设下的射流数值模拟只适用于射流近区的分析。

Streamwise vorticity, which forms in the braid zones where small three-dimensional perturbations grow strongly because of the extensional strain formed by vortex ring, collapses into counter-rotating round vortex tube.

辫子区内小扰动在涡环形成的拉伸应力的作用下快速增长，形成流向涡结构，并不断增强形成流向涡管。

By constructing a generalized function"helical solitary vortex function", the paper solves the stream function of the helical vortex tube with the help of vortex filament one, and obtains some analytical expressions for large single-vortex core and small multi-vortex core.

通过构造一类特殊的广义函数&螺旋孤涡函数&，解决了利用涡丝流函数求(来源：75AB67C论文网www.abclunwen.com)解涡管流函数问题，导出了大单和小多螺旋涡管流函数的解析解。

A new calculation model of three dimensional short foil was used to simulate the phenomenon of tip vortex and its roll up.

由端部及尾涡面上的运动学边界条件来确定端部梢涡及涡面卷曲形状。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。