向内流的

The instability originated in the upper R_B-like convection zone develops to larger region with the increase of Grashof number, and the number of non-axi-symmetric circulations decreases. When Grashof number exceeds another critical value, cooling air may invade the cavity and flow toward the shroud, the circulations decrease to one pair occupying the whole cavity in radial, thus these two zones are merged into one. The core structures in the cavity rotate against the disks, while the structures keep no change at the case of periodic oscillatory flow. With the Grashof number rises, the flow undergoes stable, periodic, periodic with cool air invading, quasi-periodic and ultimately to chaos.

离心浮升力是造成非等温轴向通流旋转盘腔内流动不稳定的主要因素，而哥氏力的存在加剧了流动不稳定性，导致流场失稳提前发生，而且在哥氏力的作用下流线发生偏转，盘腔内r-θ面出现了旋向相反的对涡，流动结构更加复杂化；随离心浮升力的继续增加，r-θ面的对涡减少，当其超过某一临界值后部分冷流体侵入盘腔，对涡减少至一对，而且沿径向充满整个盘腔；此后随离心浮升力的增加对涡的数量不再变化；r-θ面的对涡相对于盘面周向移动，但是形状基本保持不变。

The numerical results were proved to be reliable by comparing with some published experimental data. The results show that, when only Coriolis force is in effect by omitting the centrifugal buoyancy force, the flow in the cavity is axi-symmetrically stable, the Coriolis force is a kind of resilience, and does not cause flow unstably.

研究结果表明：在哥氏力的单独作用下轴向通流旋转盘腔内的流动基本上是稳定的三维轴对称结构，即使有轻微的径向或周向振动发生，由于哥氏力是恢复力，对其有抑制作用，因此振动会随着流场的发展逐渐消失。

It is proved that the problem of determining whether there is a Hamiltonian path from a specified vertex s to another t on a given digraph can be reducible at polynomial time to the problem of constructing a minimum spanning flow in a two-terminal extended network Ns,t, with the unit capacity for all arcs.

在此基础上，利用网络最小生成流的概念提出了一个修正模型，并证明了无环最小生成流问题可以在多项式时间内转换为哈密顿圈问题。文中最后指出，这一新的模型为解决在有向图内构造哈密顿轨的有效算法提供了一个新的思路和方法。

The first step of simulation method is to establish the one-dimension parabolic partial differential advection diffusion equation that was used to describe the mass transportation model of air-pollution distribution as a block program model of the controllable plant. Then, applying the Fuzzy logic theory to operate tunnel jet-fans and control the tunnel wind quantity and adjust the wind average velocity would not let the air-pollution concentration over the standard safety value too much.

模拟方式首先将常被用以表示隧道内空气污染物质传理论模式之一维向平流扩散抛物线型偏微分方程式建构成一组可控制对象的方块程式模拟模型，再运用模糊逻辑理论模拟控制喷流式通风机之运转风量来调节隧道内平均风速以控制隧道内空气污染物浓度不至於高过标准安全值太多。

Based on an analysis of distribution pattern of hydrocyclone"s axial velocity, by changing the inlet flow rate Qi and split ratio Fand making an investigation in the effect of Qi and F on axial velocity field, the factors causing the forming of short-cut circuit and circulating flow are found. It is considered that the short-cut circuit and circulating flow are produced by the structure of the hydrocyclone, and can"t be eliminated completely, though they interfere the flow field inside a hydrocyclone and affect the separation accuracy. Test results show that, by increasing Qi and F and controlling them in a certain range, the separation efficiency of the hydrocyclone can be improved.

在研究旋流器轴向速度分布规律的基础上，分析了短路流与循环流的形成原因，试验研究了改变操作参数，即改变入口流量Qi与分流比F对轴向速度场的影响认为短路流与循环流是由旋流器结构决定的，很难完全消除，它们干扰了旋流腔和大锥段的流场，在一定程度上也影响了分离精度试验结果表明，加大入口流量Qi与分流比F，并将其控制在一定范围内，便可提高分离效率这项研究对水力旋流器分离机理的认识与实际应用均有重要意义

The results of this study indicate that changing the angle of the intake port has a profound effect on the flow field during the intake stroke of the engine cycle. For the case with the intake-exhaust valves canted at zero degree (the so-called vertical valves), the tumble ratio, swirl ratio, turbulent intensity, and turbulent kinetic energy in the direction perpendicular to the bisecting plane of the cylinder are at their highest levels than those obtained for the other cases. This effect is most pronounced after the compression stroke of the cycle. As a result of this study, it is observed that the behavior of the overall flow field from the intake to the completion of compression stroke has a major impact on the effectiveness of the mixing of fuel-air prior to the ignition of the engine cycle.

结果显示，改变进排气阀的倾斜角度对进气期间的流场变化有很明显的影响，其中以垂直阀(进排气阀倾斜0度)所得的 Y轴向(Y方向系垂直於将汽缸对分为二平面的方向)滚流强度、涡漩比、紊流强度、紊流动能等流场强度为最强；若以流体经活塞压缩后的流场特性进行探讨，所得结果显示压缩冲程对汽缸内流场的效应是不容忽视的；因此由进气到压缩过程结束的整体流场现象，才是影响引擎点火前的油气混合程度与燃烧品质的关键。

The real tangential velocity fluctuation indicated that there existed an instability of swirling flow in the cyclone.This instability resulted in the rotation center of the swirling flow deviating from the geometric center of the cyclone,which produced the quasi-periodic oscillation of swirling flow and gave the real tangential velocity fluctuation.

瞬时切向速度的变化反映了旋风分离器内旋转流的不稳定性，这种不稳定性导致了旋风分离器内旋转流的旋转中心与几何中心不重合，旋转中心围绕着几何中心摆动，由此造成了瞬时切向速度随时间的类周期的波动变化。

The particles with heavy specific gravity are discharged from the underflow mouth and those with light specific gravity are discharged through the overflow pipe and thus it realizes the separation for heavy and light particles.

流体自旋流器上端给入并在旋流器内形成强制旋转流，旋转流将颗粒按粒度和比重分为内外环层，当矿浆流动至锥体部分时，由于锥体的突然变向，阻力增大，颗粒群向下运动的趋势减缓，并在此形成旋转悬浮层，随着离心力场的减弱，重力作用越来越明显，由按粒度和比重分成的内外两层逐渐转化为按比重分选的上下两层，比重大的颗粒通过底流口排出，比重小的颗粒则通过溢流管排出，从而实现轻重颗粒间的分离。

The results of calculations showed that the maximum increments in saltation height and horizontal distance due to the Magnus force were 10.2 and 24.9%, respectively, and that both increments increased with increasing lift-off angle. The maximum increments in saltation height and horizontal distance of sand grains caused by the Saffman force were only 4.6 and 3.7%, respectively. The vertical concentration distribution of Aeolian sand flow follows exponential function distribution whether or not force analysis of saltating sand grains includes Magnus and Saffman force. The effect of Magnus and Saffman force on the vertical concentration distribution of Aeolian sand current makes the rate decrease near sand bed and it is consistent with the effects of Magnus and Saffman force on the saltation height and distance of sand grains.

Magnus力对跃移高度和水平距离产生的最大增量分别可达到10.2%和24.9％，这两个增量均随起跃角度的增加而增大；Saffman力对跃移高度和水平跃移距离产生的最大增量分别为4.6%和3.7%；是否考虑Magnus与Saffman力，风沙流垂向质量百分浓度均服从指数函数分布，Magnus与Saffman力使得风沙流垂向质量百分浓度较不考虑它们的作用呈现出底层的比例较小，上层较大，Magnus与Saffman力对跃移高度的影响基本与其对风沙流垂向质量分布的影响一致，不过Magus力对风沙流垂向质量百分浓度分布影响较大，0-2cm范围内尤为强烈(7.16-10.81)，其他高度层(2-20 cm)的影响相对较小(0-2.95)。

The main contents are as follows:Based on the vortex theory and the hydrodynamic basic equations, taking account of the viscosity effect, the expressions of the tangential speed...

主要内容包括：在涡运动理论的基础上，考虑流体的粘性效应，从流体动力学基本方程出发，分析推导了旋流分离器内流体的切向速度和切向应力的分布表达式，定性讨论了旋流分离器外壁的转动对切向速度和切向应力的影响。

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。