查询词典 vortex of vector field

An elliptic rotating field is produced when an induction motor operates in asymmetry, this paper proposes a model of jointed motion to describe the motion of an elliptic rotating vector and states that the elliptic rotating vector is jointed with two components, the main one rotates forward at a uniform speed while the adjunctive one jointed at the topend of the main one rotates backward around the joint point at a double speed, both make the elliptic rotating vector rotate at swinging amplitude, speed and direction.

感应电机不对称运转时产生椭圆旋转磁场，本文建立了描述椭圆旋转矢量的接合运动模式，说明椭圆旋转矢量是由一个主矢量带动一个付矢量一起旋转构成的接合矢量，主矢量以匀速旋转，付矢量链接在主矢量顶端同时绕着链接点相对主矢量以二倍速反向旋转，两者共同构成的一个单向椭圆旋转矢量。

ABSTRACT Aiming at problems of trans-vector controller in a vehicle-carried induction motor such as variable rotor and stator resistance following motor temperature, and their inductance varying with flux saturation degrees. Firstly, CSI and VSI are introduced, for CSI, it can hold the advantages both FOC and DTC using stator flux directional, PI parameter and simulation are also introduced. Secondly, equations of IM in the synchronous rotary frame and its static counterpart, as figuring in the saturation condition of magnetic field, are dealt in this paper and the simulation results are presented. Thereafter, the parameter designing of PI trans-vector controller is processed, which features the non-linear model. In practical realization, as neglecting the dynamical change of motor inductance, this paper employs online modification of inductance parameters, according to the flux saturation, then transforms the non-linear equations into linear ones, and so compacts the structure of controller. Thirdly, in view of the maximum torque output is extraordinary requisite when Electrical Vehicle start up, accelerate, and overtake, this paper issues the maximum torque when both inverter and battery capacity is corporeally definite. Fourthly, on-line differentiating and analyzing both rotor's time constants and its flux by using the expanding order reduction and discrete Kalman filter equation are fathomed, in order to realize high-performance trans-vector algorithm, and also the simulation results are presented. Fifthly, the close-loop regenerative brake system, when the EV's torque is set constant, is deduced; at the same time, unification of electric drive model and brake model is executed. Combined with maximum charge current demands, the mathematical model for online yielding torque as a demand.

本论文针对车载异步电机在矢量控制器所遇到的问题：定转子电阻随温度变化及随电机饱和程度变化的转子电感及定子电感而影响电机调速性能提出一套完整的解决方案：分析了电流型逆变器和电压型逆变器在实现矢量控制时控制器参数的计算，分析出对于电流型逆变器在采用定子磁场定向时，其性能同时具有矢量控制和直接转矩控制两者的优势，并对电压型逆变器在转子磁场定向下的模型进行了仿真研究；建立异步电机非线性模型，推导出考虑磁饱和时异步电机在同步旋转坐标系及静止坐标系下的方程，并做出了仿真结果，建立异步电机在非线性模型下的矢量控制调节器的PI参数设计，在实际应用中，若忽略电机电感的动态变化，可以根据当前的磁路饱和状态而在线修正电感参数，从而将非线性方程线性化，降低控制器的复杂度；考虑到电动汽车在起动和加速超车时需要电机有最大转矩输出，本文讨论在逆变器容量一定和电池供电能力有限的情况下电机最大转矩输出问题；推导了异步电机扩展降阶、离散卡尔曼滤波方程在线辨识转子时间常数和转子磁通，用于实现高性能的矢量控制算法，并给出了仿真结果；推导出了电动汽车恒转矩给定的闭环回馈制动系统，实现了电动控制模型和制动模型的统一，而且结合铅酸电池最大充电电流的要求，为制动转矩在线给定建立了数学模型；设计了基于双DSP系统的高性能矢量控制器软硬件框图，并以大量实验数据说明矢量控制在电动汽车应用的实际应用状况。

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。

Downstream axially from nose apex to afterbody,a local sectional-side-force extremum always presents itself behind the forming of the corresponding shed vortex and new lee-side vortex.

沿轴向从头部尖顶往后体，截面侧向力局部极值的形成总是滞后于相应脱落涡、新生背涡的形成，截面侧向力局部极值的大小同时取决于相应脱落涡、新生背涡的形成方式和相应背涡的强度。

By direct numerical simulation of Navier-Stokes equations we investigate the three-dimensional evolution of a mixing layer, the three-dimensional merger of two parallel vortex tubes and reconnection of two antiparallel vortex tubes in the thesis.

本文用拟谱方法求解Navier-Stokes方程，对小扰动下平面混合层随时间的演化、同向平行涡管的三维合并和反向平行涡管的重联进行了直接数值模拟。

The center of northern polar vortex is not at Arctic pole. The center of polar vortex mainly displace towards Asia, departure form Europe, but stronger trend to the Pacific....

极涡呈现偏心结构，极涡中心位置主要偏向亚洲大陆，偏离欧洲大陆，但有较强的偏向太平洋一侧的趋势。

Here j is an auxiliary line current that flows along vortex cores, and for each vortex takes an

这里j是沿著旋涡核流动的辅助流线，对每一个旋涡取等於量化通量l 的整数值。

Herej is an auxiliary line current that flows along vortex cores, and for each vortex takes an

这里j是沿著旋涡核流动的辅助流线，对每一个旋涡取等於量化通量l 的整数值。

By means of the new analysis method of vortex centripetal force, the author analyzed the cause of vortex street formation.

在对涡街成因分析时，作者采用了新的涡的向心力分析方法。

N experiment combining flow visualization and temperature measurement is carried out in the present study to investigate the possible presence of new inertia-driven vortex rolls and some unique characteristics of the time-dependent mixed convective vortex flow resulting from a high speed round air jet impinging onto a heated horizontal circular disk in a vertical cylindrical chamber.

bstract：本篇论文利用实验流场观测方法及温度场量测方法对於垂直圆柱容器中一高速空气圆形喷流冲击至一加热圆盘之可能产生新的惯性力驱动涡流和一些独特的周期性混合对流涡流流场特性进行研究。

We have limited budget let me know if you can do this competitively.

我们有限的预算让我知道如果你能做到这一点竞争力。

We don't know how other critters breathe--lizards, for example.

我们还不知道诸如蜥蜴之类的动物如何呼吸。