查询词典 vortex flow

The results show that, when the fuel supply position is located at the forebody of cavity, the jet flow of fuel supply has certain damage to vortex, and when the fuel supply injection is located at the afterbody of cavity, the jet flow of fuel supply has no damage to vortex.

实验表明，供油位置在凹腔前体，油气掺混孔处的射流对涡有破坏，供油位置在凹腔后体，油气掺混孔处射流对涡没有破坏作用，在不考虑供油方式等因素的情况下，凹腔后体供油优于凹腔前体供油。

The transverse wave disturbance along tangential base flow of circular vortex is discussed By using numerical method we study this instability of baroclinic flow which is mesoscale inertia wave instability on the cylindrical coordinate The influence of stratification stability N 2 , Coriolis parameter f 0 , the vertical shear of tangential wind z of the ambinent atmosphere and the latent heat on the growth rate of instability is studied From the above analysis and calculation, we can learn that there are Eady mode and mesoscale mode of transverse wave instability in circular vortex as well Furthermore we also learn that distribution character of mesoscale mode disturbance field of transverse wave instability, anomalistic "cats eye" structure of lower level and the character of the slowly spreading disturbance converges at low level and the quickly spreading disturbance converges at high level

作者中文名：李红金；陆汉城；宋晓亮；李鲲摘要：讨论涡旋大气中，存在沿切向基流传播的横波型扰动，并采用数值方法讨论了柱坐标系下圆形涡旋系统斜压气流中这类扰动的不稳定，这是一类中尺度的重力惯性波的不稳定。研究了涡旋环境大气的层结稳定度参数N2、切向风垂直切变Vz、凝结潜热、涡旋特性及科里奥利参数f0对不稳定增长率的影响。圆形涡旋中同样存在横波不稳定的Eady模态和中尺度模态，得到了中尺度模态的扰动场分布特征：流场的不规则"猫眼"结构及慢速传播的扰动均集中在低层，而快速传播的扰动均集中在高层的扰动特征。

It is shown from this thesis that flow fields on synoptic maps can be decomposed into rotation and deformation fields. Geostrophic non-frictional cyclone and anticyclone vortex patterns are closed circulations around the center point, streamlines of frictional cyclone and anticyclone patterns have spiral forms around the focus point. Saddle fields have four vortex centers (two cyclones and two anticyclones) and a saddle point. Blocking high pressure and cut-off low pressure patterns consist of a vortex center and a saddle point.

本文说明了天气图上的流场可以分解为旋转场和变形场：地转无摩擦的气旋、反气旋的涡旋型式是围绕中心点的闭合环流；考虑摩擦的气旋、反气旋的流型是围绕焦点的螺旋型式；鞍型场有4个涡旋中心点（2个气旋和2个反气旋）与1个鞍点；阻塞高压和切断低压由1个涡旋中心点与1个鞍点组成。

Based on the above study, a program is developed which calculate the modeled subgrid stresses, and is applied to simulate the turbulent flow in a plane channel. The computational result is compared with the data extracted form a DNS database, and the agreement is satisfactory. A numbers of physical phenomenon has been reproduced in the simulation, including hairpin vortex and counter-rotating rolls in near wall region, intermittent vortex structure, the maximum of pressure clustering in wall area and the high-speed fluid sweep into the low speed fluid, and the ability of the LES to simulate turbulent flow is well shown.

在对LES技术学习掌握的基础上，编制了亚网格模型的计算程序，在三维平板通道流动的具体计算中应用大涡模拟技术，并与DNS计算结果进行了比较，得到了满意的结果，三维通道中的重要流动现象被很好的预示出来，包括近壁面的发卡涡，对旋涡，间歇猝发涡结构，压力最大值向壁面的倾斜，高速流体对近壁面流体的下扫，卷掠等，显示了大涡模拟技术对湍流流动模拟的能力。

After analyzing the performance anduncertainty of the DDPM vortex flowmeter in gas-liquid bubble flows, the vortexflowmeter-Venturi tube combinative method using the vortex flowmeter and the Venturi tube as measuring cells was put forward, the measurement model based on thevortex frequency and the Venturi differential pressure was established, and it showsthat the relative errors of this method for the mass flow measurement of bubble flowsare within±5%. Furthermore, the flowrate and volume void fraction of bubble flowswere obtained using a single DDPM vortex flowmeter through the relationshipbetween the frequency and amplitude of the circumferential DDPM signal, and resultsdemonstrate that the relative errors of the flowrate and volume void fraction of bubbleflows are within±5% and±10% respectively, which indicates the broad applicabilityof this method to large numbers of engineering fields.

通过分析管壁差压式涡街流量计在气液泡状流中的性能和不确定度，提出了以涡街流量计和文丘里管作为测量元件的&涡街—文丘里联合法&，建立了以涡街频率和文丘里差压为被测量的测量模型，该方法对气液泡状流质量流量的测量相对误差可达±5％；通过建立涡街周向管壁差压信号频率和幅度与被测流体的关系，使用单个涡街流量计实现了对气液泡状流流量和体积含气率的双参数测量，该方法对气液泡状流流量和体积含气率的测量相对误差分别为±5％和±10％，可以满足大量工业实际应用的要求。

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 above problems are studied in this thesis. First, the implicit NND scheme with mix flux splitting method proposed by Zhang Hanxin that is first order accurate in time and second order in space is modified. The modified scheme keeps the characteristics of fast convergence and is second order accurate both in time and space. It can be capable of simulating the unsteacly flow. Second, the topological method founded by Zhang Hanxin is improved to study the characteristics of vortex near the singular point on its axis and the cross streamlines on the longitudinal section passing the vortex axis. On the basis of topological results, a program which visualises numerical results is made out. It can help us analyse the characteristics of vortex motion.

本文对上述问题做了研究：第一，在数值模拟方面，借助于张涵信提出的NND算法和混合通量法，我们将他建立的时间为一阶、空间为二阶精度的快速隐式算法推广为时间和空间均为二阶精度的算法，这样做保留了原格式收敛快的特点，而且能适用于真实的非定常流态的计算；第二，将张涵信的拓扑分析方法加以推广，研究了涡轴附近及破裂点邻域内流场的空间特征，并以这些拓扑分析结果为指导，研制了一套显示计算结果的软件，这一软件能很好地帮助我们分析流场的计算结果和旋涡演变的特征。

The scale and strength of passage vortex is also simulated in the flow filed incascade with straight and positively curved blade by using total 3D N-S solver.The results indicate that the passage vortex which is the main part of thesecondary flow can be limited in small-scale steady shape by using curved blade.

借助于全三维N-S方程的求解程序，对直叶片和弯叶片两种流场中的通道涡的尺度和强度进行了数值模拟，模拟结果表明，采用弯叶片可使对二次流起主要作用的通道涡限定在尺度较小的稳定形式上。

When the positive curving angle increases, the total losses of cascades increase, the outlet flow angles vary acutely along the spanwise, the intensity and size of outlet trailing vortex increase obviously, however the intensity and scale of outlet passage vortex vary slightly, secondary flow at both midspan and endwall increase and the total averaged kinetic energy of secondary flow increases..

随着叶片正弯曲角的增大：叶栅总损失增加；叶栅出口气流角沿叶高剧烈变化；叶栅出口尾缘涡的强度和尺度明显增大，而叶栅出口通道涡的强度和尺度变化都不大；叶栅中部和端部二次流均增强，总平均的二次流动能增大。

Through the details simulation calculation of typical operation conditions of turbine, some conclusions are showed: the design of the overflowing parts is appropriate; the flow in the draft tube is smooth in the optimal operation conditions, the rotation direction of the vortex band is reversed to the runner in the large flow, and the rotation direction of the vortex band is identical to the runner in the small flow.

通过对水轮机典型工况点的详细计算分析，可以看出：各过流部件的设计符合设计要求；同时在最优工况下，尾水管没有明显的偏心涡带，在大流量工况下，尾水管直锥段内有与旋转方向相反的涡带；在小流量工况下，尾水管直锥段内有与旋转方向相同的涡带。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。