涡流

Based on the principle of PEC, surface cracks mainly affect the high frequency components and subsurface crack mainly affect the low frequency components, so the PEC signals can be analyzed in frequency domain, which can eliminate the influence of noises during measurement. A method of frequency spectrum separating point is proposed for flaw classification, which enhances the accuracy in classification of defects. The agreement between theory and experiment shows that the present method is valid and applicable.

通过对脉冲涡流的理论分析发现，表面裂纹主要影响脉冲频谱中的高频成分，而表面下裂纹主要影响脉冲频谱中的低频成分，因此可以将时域中易受噪声影响的脉冲涡流信号变换到频域分析，提出了"频谱分离点"的方法来对裂纹进行分类识别，提高了缺陷分类识别的正确率，理论分析和实验结果相一致，证明了该方法的正确性和有效性。

Based on this, the optimized experiments for matching between the fuel injection system and combustion chambers with different reentrant diameter have been done.

同时试验研究了涡流强度保持性与喷射系统参数、进气涡流匹配时对柴油机性能的影响。

Therefore, compensation for the drift should be given; the main reason for the temperature drift is theoretically analyzed which lies in the temperature coefficient of the coil resistance, and then a new compensation method utilizing non-inductive winding is presented and illustrated in an example; the experimental results show that the sensor obtains good compensation effects under 20-90℃, and the temperature stability reaches 0.7%.

电涡流传感器的温度漂移制约了其测试精度，因此需要给以温度补偿；理论分析出导致传感器温度漂移的主要原因在于线圈电阻的温度系数过大，因此提出采用无感线圈进行补偿的方法，并给出了设计实例；实验表明该方法在20~90℃度范围内补偿效果良好，温度稳定性达到0.7%；该方法简单、有效且成本低，可扩展应用于其他类型电涡流传感器。

For the purpose of real-time position inspection of components with large curved metallic surfaces by using a flat flexible eddy current sensor array,the measurement technology is investigated and the testing method based on time division multiplexing technology is introduced for the eddy current array.

采用一种基于时分多路的电涡流阵列测试的方法，通过对传感器探头和测试电路的合理设计，使系统电路得到简化，减小阵列单元之间的串扰，提高传感器系统的测试性能，实现了电涡流传感器阵列的快速、高精度测量

Based on Prandtl's momentum transportation, this paper calculates in detail the physical quantities such as eddy viscosities, and ratio of eddy viscosity to motion viscosity, total stresses with respect to relative position in three regions of viscous sub-layer, buffer layer, and main turbulent stream for non-Newtonian fluid flowing turbulently in ducts, which according to Karman's three layer models and measurement of fluid parameters in evaluation apparatus, discusses the influence of polymer drag reduction on flowing properties of non-Newton fluid, analyzes quantitatively principle of turbulent reduction phenomenon and condition of increasing reduction rate.

摘要以普兰德动量传递理论为基础，按照卡门的三层模型，通过室内模拟环道用0号柴油及加入减阻剂在圆管内的流动参数的测定，计算了非牛顿型流体管内湍流边界层的层流内层、过渡层、湍流中心的涡流粘度，涡流粘度与运动粘度比、总应力随相对位置的变化等定量参数，探讨了高分子减阻剂对非牛顿流体流动特性的影响，对湍流减阻现象的机理与增大减阻率的条件进行了定量分析。

Secondly,with the influence of inlet whirlpool and compress stroke,the oil beam and the fire mass rotate around the cylinder center line accompany with vortex of inertia.

受进气涡流影响和压缩冲程的连续作用，喷射阶段的油束和燃烧阶段的各个火焰团都随涡流惯性而围绕汽缸中心线转动。

Both the scattering and rheological results indicated that the phenomenon similar to"double cloud point", which has been found along the vorticity direction by previous studies, could be also observed in the velocity direction, which confirms the prediction of the above theory that the polymer blend will exhibit anisotropical complex phase diagram under shear. It's also found that the mixing along vorticity direction was reduced by weak shear but enhanced by strong shear. In addition, the more remarkable the molecular weight differences between components, the more prominent the shift of the apparent phase boundary along vorticity direction.

除了以往研究发现涡流方向存在&双浊点&现象以外在，本文的光散射和流变测试均显示，剪切场下体系在流动方向上也出现了类似&双浊点&的现象，证实了上述理论模型关于剪切场会导致二元高聚物共混体系出现各向异性的复杂表观相图（例如Miscibility Gap现象）的预测；同时发现弱剪切会导致体系涡流方向上的相容性减小，而强剪切则在该方向上增强相容性；另外，两组分分子量的差异越大，表观相界的移动越显著。

Next the discussion in this study, about an ellipse with an angle of attack and two circular cylinders with different diameters in the flow, the aim of this study is investigated for the ability of the present numerical method by solving the suppression of the vortex shedding flow behind the two-cylinder system which was kind of difficult to reach by a Cartesian grid method. In this study, the suppression of the vortex shedding flow is tested to solve a uniform flow past through two different diameter cylindrical in the flow field with Fractional Step Method and Immersed Boundary Method.The numerical method which we investigated is showed that the results of the problem is appropriable in other literatures.

接著探讨流过具攻角之椭圆柱体流场及流过圆柱抑制涡漩逸出之流场，目的是要研究利用控制圆柱来抑制下游涡流的流场行为，本文采用分步法配合内嵌边界法数值解析一均匀流流经两不同直径的圆柱流场，来测试抑制涡流逸出的问题，根据现有的数值结果发现试验运用了合适的方法且得到令人满意的结果。

Based on new style equivalent source method of axisymmetrical static field, this paper proposes a new style equivalent source method of axisymmetrical eddy current field , in which the number and positions of all the ES can be determined and the field distribution in all subregions is expressed in series form.

本文把轴对称静态场中的新型等效源法推广到轴对称涡流场中，提出了轴对称涡流场的新型等效源法，该法中等效源的位置和个数可给以确定，由它产生的场分布可用级数表示，克服了以前等效源法中等效源的位置和个数只能凭经验决定的缺点。

Compressed Air circumrotate at a high speed in the vortex tube, divided into two different airstreams after vortex in the vortex room, the air in the center of the tube have low temperature, and the air temperature out of the tube higher, adjust the rate of air in cooled and hot, we can get better refrigeration effect and hot effect.

气流在涡流管内高速旋转时，经过涡流变换后分离成总温不相等的两部分气流，处于中心部位的气流温度低，而处于外层部位的气流温度高，调节冷热流比例，可以得到最佳制冷效应或制热效应。

Do not gum up the work by telling mother what we are going to do .

别告诉母亲我们要干的事，那会把事情搞糟的。

In recent years, application of the partial prestressed concrete beam s is developed.

近年来，随着部分预应力砼梁应用的推广，发现我国规范所采用的名义拉应力法的计算结果不稳定。