查询词典 vortices

1The axial evolution law on the structure and the aerodynamic characteristics of the asymmetric flows around slender bodies of revolution at incidences is summarized:whether the flow asymmetry is powerless or powerful,the flow always appears in the structure that lee-side vortices rise,and shed vortices form,and new lee-side vortices come into being alternately on opposite sides of a slender body of revolution axially from nose apex downstream to afterbody,and always induces the sectional side force of waving quasi-sinusoidally downstream axially.

1总结出细长旋成体有攻角非对称绕流流场结构和气动力特性的轴向演化规律：无论非对称性强弱，沿轴向从头部尖顶往后体，非对称绕流总是呈现为左、右两侧背涡交替从物面向上飘起、形成脱落涡、再衍生出新生背涡的流场结构，并诱导出沿轴向呈类似正弦曲线形式振荡分布的截面侧向力。

The results show that, when the computational error and its accumulation are eliminated effectively, the laminar flow in OFR with perfect-symmetric boundaries behaves in a pattern of central symmetry and circumferential uniformity while the turbulent flow field presents a centrally symmetric and circumferentially non-uniform structure with 8 transverse vortices arrayed circumferentially in a way of central symmetry, similar to Taylor vortices in Couette flow.

模拟结果表明在有效消除计算随机误差以及误差积累的情况下，几何边界理想对称OFR内的三维层流流场呈现出良好的中心对称性和周向均匀性，而湍流流场中心对称的同时呈现出周向非均匀结构－在圆周上生成8个中心对称排列的横向漩涡，其形态与Couette流中的泰勒涡类似。

PIV experiments were performed to study Kelvin-Helmholtz discrete sub-vortices. Numerical simulation was performed to study this phenomena and spectrum of the discrete sub-vortices is discussed.

利用PIV实验对剪切层中由Kelvin-Helmholtz不稳定性引起的小涡运动状态进行了分析，对小涡脱落频率进行了统计；进而利用数值模拟的方法，也得到小涡脱落的频谱。

A systematic study of correlation between nose disturbances and evoluted behaviors of asymmetric vortices over slender body models has been conducted. The new flow phenomena have been revealed in which the two-cycle behavior of Cy vs.γ curve for asymmetric vortices flow is continuously changed into one-cycle behavior with increasing of disturbance strength on the model nose tip. This newly found flow phenomenon is important and it provides a physical flow base to the perturbation active control of forebody asymmetric vortices flow.

系统研究并获得了头部人工微扰动的形式、位置和强度与非对称涡响应演化之间的相关关系，揭示了前体非对称涡系随头部扰动强度的变化呈现出由双周期向单周期连续演化的新现象，它为实现前体非对称涡的扰动主动控制提供了流动的物理基础，以此提出了单孔位微吹气扰动主动控制新技术。

In chapter 1, an up to now synthetically evaluation is given on the research ways and conclusions about jet in cross-flow. Considering the shortage of previous research ways and techniques (the instantaneous flow field and vortices field can not be properly get), in addition to the deficiency of corresponding conclusion (mainly concentrate on the analysis of time-average but little on structures of flow and action of vortex), the research way and content is draft out in this part. Though PIV, the time-average, instantaneous flow field and vortices field can be get, that will unveil the coherent vortex and its course of generation, development and evolvement, with the assistance of K-ε model and Hybrid Finite Analytic Method , which will proof-test the experiment result and bring some complementary, more profound research about the 3-D characters can be done. Using some fundamental topological theory and principle on flow analysis, with anglicizing of vortex structure, a reasonable description is the topological characteristic of near field in JICF given.

首先在第一章中对横流中湍射流的以往研究方法和研究成果给予了综合的评述，针对横流中湍射流旋涡结构以往研究中研究方法的局限性（不能很好得到流动的瞬态流场及涡量场）和相应研究成果中存在的不足（大都集中在时均特性的分析，对流动的内部结构和旋涡的运动阐述很少），明确了本文的研究方法和研究内容：通过PIV流动测量显示技术得到流动的时均及瞬态流场、涡量场，来揭示横流中湍射流的时均、瞬态流场、涡量分布特性，和各种具有拟序结构性质的复杂涡系的产生、发展及演化过程；结合湍流k-ε双方程模型及相应的HFAM计算方法，对于实验进行相互验证和补充，从而更为充分地研究各种旋涡的三维特性；利用拓扑分析的一些基本原理及相关规则，依据对各种旋涡结构的分析，做出对射流近区流场拓扑性质的合理描述。

Rotate the model to better view the 3D structure of the vortices.

把模型旋转到vortices的更好的观点3D结构。

It is revealed that the asymmetric vortices over slender body are formed the breakaways of higher position vortex and generation of new vortex, which are alternately developed on the both sides along the body axis. The correlation between asymmetric vortices structure and distribution of sectional sideforce coefficient has been obtained. A physical model of asymmetric multi-vortices flow structure is developed according to zonal flow analysis.

在此基础上揭示了非对称涡系是通过细长体两侧背涡沿轴向交替脱落、新生而形成的，给出了非对称涡系沿轴向演化、发展的流动结构和截面侧向力分布特性之间的相关关系，在分区分析的基础上提出了非对称涡系结构的物理模型。

The shear layer vortices dominate in the initial portion of the jet, which are a result of the K-H instability. The crossflow encounters an adverse pressure gradient ahead of the jet and separates to form horseshoe vortices under the pressure downstream, and they develop into the wake. The wake vorticity comes into being in the actions of an adverse pressure gradient and a wall-normal component of vorticity, which originates from the wall boundary and is entrained into the jet. The shear layer vortices encounter adverse pressure gradients in the lee of the jet and break down, leading to the formation of the CVP and the CVP is the most important characteristic of the jet in crossflow.

文中指出：剪切层涡源于射流与横流之间的K-H不稳定性；马蹄形涡的产生是由于射流喷口上游迎风侧的壁面边界层内存在逆压梯度，使流动发生了分离，在下游逆压梯度的挤压作用下，形成了马蹄形涡，马蹄形涡向下游发展，进入尾迹区；在逆压梯度和法向涡生成项的共同作用下产生了尾迹涡，尾迹涡源于壁面边界层，止于射流，并将部分涡量向上输运至射流内部的CVP；CVP是横向紊动射流的重要特征，剪切层涡破裂后，在逆压梯度的作用下CVP形成。

Main advances of research on vortices in pump sumps;2. Based on flow field analysis,it shows that owing to the wakes behind the upstream suction pipe,the downstream flow becomes more turbulent and appears with obvious free-surface vortices and submerged vortices in complicated movement.

本文在玻璃水槽内对不同管间距条件下的吸水管周围进行了大量的PIV流场量测实验，通过流场分析显示，上游吸水管的尾流作用加剧了下游吸水口的水流紊动强度，流场多处出现表面旋涡和水内旋涡，其运动形态复杂多变。

By using several thousands of point vortices and small space mesh, we obtain the large scale discrete vortices on the vortex sheet as result of the pairing of small point vortices, thus simulate the instability phenomena of the rolling-up vortex sheet.

由于使用了数千个点涡和较小的空间网格，获得了前缘涡层小涡配对出现的较大的离散涡，模拟了紧卷涡层的不稳定现象。

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

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