脉动

The Cholesky decomposition of cross spectral density matrix was approximated and reduced, and then the modified spectral representation method is efficient and requires less computer memory, which is suitable for simulating spatial wind fields of long span bridges.

针对现有Deodatis方法模拟大跨度桥梁空间脉动风场中存在的计算量问题，通过对谱分解矩阵引入插值近似，减少谱分解的次数，从而提高该谐波合成法的计算效率，并节省内存花费，实现了对三维空间脉动风场的有效模拟。

This paper discusses the principle of the torque ripple of BLDCM with focuses on the theoretical analysis of the relationships between torque ripple and parameters of windings,motor speed and bus voltage,as well as 3-phase reverse electrodynamic potential during phase converting.

对永磁无刷直流电机的换相转矩脉动的产生机制进行了分析，主要从理论上探讨了换相引起的转矩脉动与电机绕组的参数、换相期间的三相反电动势、电机的运行速度及母线直流电压等之间的关系。

As the first attempt, this paper applies the laminar flamelet model to the typical diffusion combustion in diesel engines. A database of the laminar flamelet for a DI engine is built up in the phase space of the mixture fraction with the scalar dissipation rate as parameter.

以KIVA-3程序为基础，摒弃其原有的化学反应模型，模拟内燃机缸内多维湍流流场，并补充求解混合分数的时均值及其脉动均方值的湍流输运方程，得出各曲轴转角下混合分数的时均值及其脉动均方值的缸内空间分布。

The laminar flamelet model in combination with joint probability density function transport equation of mixture fraction and turbulence frequency is used to simulate fluctuating behavior of radiative source term in turbulent jet diffusion flames of hydrogen.

采用κ-ε湍流模型、标量联合的概率密度函数输运方程和层流火焰面模型相结合，模拟氢气自由扩散火焰中辐射源项湍流脉动特征。给出了主燃区内辐射源项湍流脉动的频率图。辐射源项的样本点分布集中，大约95%以上的样本落在其系综的±3倍方差以内，频谱图为单峰

In order to improve the mechanical performance and transmission efficiency of the traditional pulsed mechanical continuously-variable transmission,a novel pulsed CVT is proposed according to the linear characteristic of hypocycloid at specific parameters and by combining the planet gear transmission mechanism with the crank slide block mechanism.

针对脉动式无级变速器动力性能差、效率低下等缺点，利用内摆线在特定条件下为直线的特性，将行星齿轮传动机构与曲柄滑块机构相结合，提出了一种新型脉动式无级变速装置。

In this paper, the stationary and non-stationary random wind-induced response, dynamic reliability and optimization under the dynamic reliability constraint of structures with foundation rotation and tall building with TMD or TLD is studied systematically. Three achievements are gained. 1. According to the situation that Davenport wind spectrum is irrational fraction, the equivalent wind spectrum is generated by linear filtered process.

本文对基础转动结构、带TMD或TLD结构的高层建筑和高耸结构的平稳与非平稳随机风振响应、动力可靠性分析以及基于动力可靠性约束的优化设计方法进行了系统的研究，取得了以下成果：1、针对Davenport脉动风谱为非有理分式风谱，通过线性滤波过程和三参数拟合，生成了与Davenport风谱等效的脉动风谱。

Under partial load conditions the draft tube 3D simulation results showed that the climax of pressure fluctuation of draft tube vortex incepted at the underside of cone part closed by bend and the frequency of the pressure fluctuation accorded with times frequency rule very well.

部分负荷工况下尾水管内三维非定常计算结果表明，尾水管涡带压力脉动最大发生在直锥段下面靠近弯肘段，并且脉动频率符合实际的倍频规律，从而验证了简化公式的正确性。

The frequency at the point of maximum amplitude is close to the blade passing frequency.

首次分析了不同轴截面的压力脉动，其脉动曲线基本相同。

The calculafion results show that the oscillating pressure in shallow water is different from that in deep water.

计算结果表明浅水脉动压力与深水脉动压力的分布规律明显不同。

The pulsate pressure in high speed flow water will influence the safety of water construction, and the eigenvalue of the pulsate pressure should be confirmed by hydraulic model testing.

高速水流中的水流脉动对水工建筑物的安全运行存在很大的影响，水流脉动压强的特征值一般需通过水工模型试验确定。

They weren't aggressive, but I yelled and threw a rock in their direction to get them off the trail and away from me, just in case.

他们没有侵略性，但我大喊，并在他们的方向扔石头让他们过的线索，远离我，以防万一。

In slot 2 in your bag put wrapping paper, quantity does not matter in this case.

在你的书包里槽2把包装纸、数量无关紧要。