Effects of rotation and tidal distortions on the shapes of radial velocity curves of polytropic models of pulsating variable stars

Anharmonic oscillations of rotating stars have been studied by various authors in literature to explain the observed features of certain variable stars. However, there is no study available in literature that has discussed the combined effect of rotation and tidal distortions on the anharmonic oscillations of stars. In this paper, we have created a model to determine the effect of rotation and tidal distortions on the anharmonic radial oscillations associated with various polytropic models of pulsating variable stars. For this study we have used the theory of Rosseland to obtain the anharmonic pulsation equation for rotationally and tidally distorted polytropic models of pulsating variable stars. The main objective of this study is to investigate the effect of rotation and tidal distortions on the shapes of the radial velocity curves for rotationally and tidally distorted polytropic models of pulsating variable stars. The results of the present study show that the rotational effects cause more deviations in the shapes of radial velocity curves of pulsating variable stars as compared to tidal effects.

Effect of interaction of the various modes on the radial velocity curves of the polytropic models of rotationally and tidally distorted pulsating variable stars

In our previous work, we developed a model to study the effects of rotation and/or tidal distortions on anharmonic radial oscillations and hence on the radial velocity curves of the polytropic models of pulsating variable stars.We considered the first three modes(fundamental and the next two higher modes) for the polytropic models of index 1.5 and 3.0 in that work.In the present paper, we are further extending our previous work to study the effect of the interaction of various modes on anharmonic radial oscillations and hence on radial velocity curves of the rotationally and/or tidally distorted polytropic models of pulsating variable stars.For this purpose, we have considered the following cases:(i) fundamental mode(ii) fundamental and the first mode,(iii) fundamental and the next two modes and finally(iv) fundamental and the next three higher modes of pulsation in our study.The objective of this paper is also to investigate whether the interaction of various modes affects the results of our previous study or not.The results of this study show that the interaction of the fundamental mode with higher modes appreciably changes the shape of the radial velocity curve of rotationally distorted and rotationally and tidally distorted polytropic models of pulsating variable stars.

Profile Measurement of Ion Temperature and Toroidal Rotation Velocity with Charge Exchange Recombination Spectroscopy Diagnostics in the HL-2A Tokamak

This paper deals with the profile measurement of impurity ion temperature and toroidal rotation velocity that can be achieved by using the charge exchange recombination spectrum （CXRS） diagnostics tool built on the HL-2A toknmak. By using CXRS, an accurate impurity ion temperature and toroidal plasma rotation velocity profile can be achieved under the condition of neutrM beam injection （NBI） heating. Considering the edge effect of the line of CVI 529.06 nm （n= 8-7）, which contains three lines （active exciting spectral line （ACX）, passivity exciting spectral line （PCX） and electron exciting spectral line （ICE））, and using three Gaussian fitted curves, we obtain the following experimental results： the core ion temperature of HL-2A device is nearly thousands of eV, and the plasma rotation velocity reaches about 104 m· s^-1. At the end of paper, some explanations are presented for the relationship between the curves and the inner physical mechanism.

Measurement of the Plasma Rotation Velocity by Using Visible Spectrum on HL-1M Mokamak

The plasma rotation velocity were measured in HL-1M with Doppler shifts of CⅢ、 C Ⅱ、 O Ⅱ and H. line by a SKD high resolution spectrometer. The effects .of density' hydrogen pellet injection and carbon impurities injected by laser-blow-off on toroidal(V) and poloidal (Vθ)rotation velocity have been observed. The Vθ measured from H. line is only half of that from C Ⅱ impurity line.

A New Method for Measurements of the Poloidal Rotation Velocities and Wavelength Calibration of X-ray Imaging Crystal Spectrometer in Magnetic Fusion Devices

A new simple method is presented for the wavelength calibration and measurement of poloidal rotation velocities with X-ray imaging crystal spectrometer（XICS）in magnetic fusion devices.In this method,the toroidal rotation of plasma is applied for high precise alignment and wavelength calibration of the poloidal XICS.The measurement threshold of poloidal rotation velocity can be lowered to 1-3 km/s with this method.

Rotational nanofluids for oxytactic microorganisms with convective boundary conditions using bivariate spectral quasi-linearization method

In this study,we considered the three-dimensional flow of a rotating viscous,incompressible electrically conducting nanofluid with oxytactic microorganisms and an insulated plate floating in the fluid.Three scenarios were considered in this study.The first case is when the fluid drags the plate,the second is when the plate drags the fluid and the third is when the plate floats on the fluid at the same velocity.The denser microorganisms create the bioconvection as they swim to the top following an oxygen gradient within the fluid.The velocity ratio parameter plays a key role in the dynamics for this flow.Varying the parameter below and above a critical value alters the dynamics of the flow.The Hartmann number,buoyancy ratio and radiation parameter have a reverse effect on the secondary velocity for values of the velocity ratio above and below the critical value.The Hall parameter on the other hand has a reverse effect on the primary velocity for values of velocity ratio above and below the critical value.The bioconvection Rayleigh number decreases the primary velocity.The secondary velocity increases with increasing values of the bioconvection Rayleigh number and is positive for velocity ratio values below 0.5.For values of the velocity ratio parameter above 0.5,the secondary velocity is negative for small values of bioconvection Rayleigh number and as the values increase,the flow is reversed and becomes positive.

Turbulent Wind Field Simulation of Wind Turbines With Rotational Effects

为准确得到风轮旋转效应对风力发电机组湍流风速脉动分量的影响，推导了旋转Fourier自谱和互谱。分析了风轮旋转效应通过相干函数和相位延迟体现的物理本质，提出了引入相位延迟参数的旋转Fourier自谱和互谱。以旋转Fourier自谱和互谱的模构建旋转谱矩阵，对其进行Cholesky分解，将相位延迟引入谱表现方法中实现风力发电机组湍流风场的模拟。最后，结合某1．5Mw三叶片变桨距风电机组进行纵向脉动风速时程的数值模拟，并对计算功率谱与目标谱进行了校核，证明该文算法可以更为准确地模拟作用在风轮旋转叶片上的脉动风速时程。

Apparent velocity estimation with P-SV ratio method

The apparent velocity of the incident wave is an important parameter for simulating rotational ground motion with theoretical methods, but it is difficult to estimate effectively when there is only a single record. This paper discusses a P-SV ratio method based on elastodynamic theory in a multi-layer isotropic elastic half space. The apparent velocities of four earthquakes in the SMART1 array are calculated with this method. The result is close to a method that uses travel time analysis. Furthermore, the factors that impact the apparent velocity and equivalent incident angle are considered according to records from the Chi-Chi earthquake. There is no obvious relationship between the equivalent incident angle and epicenter distance. However, the equivalent incident angle is obviously dependent on the site conditions.

Real-time measurement of high rotational projectile axial acceleration based on 2-axis acceleration sensor

The real-time measurement principle of high rotational projectile＇s angular velocity based on 2-axis acceleration sensor and the axial acceleration measurement error caused by the installation error are discussed.The 2-axis acceleration sensor is applied to measure the high rotational projectile＇s angular velocity and the measurement value of axial acceleration,the axial acceleration of the high rotational projectile equals the measurement value of axial acceleration subtracting the centrifugal acceleration component,so that the high-accuracy real-time measurement of axial acceleration is realized.The memory test has confirmed the strike tally of the theoretical analysis and the test result.The measurement technique can satisfy the high-accuracy measurement of the high rotational projectile axial acceleration in the self-determination course correction fuze projectile.

The Physics of Rotational Flattening and the Point Core Model

The effect of rotation on the shape (figure) and gravitational quadrupole of astronomical bodies is calculated by using an approximate point core model: A point mass at the center of an ellipsoidal homogeneous fluid. Maclaurin’s analytical result for homogenous bodies generalizes to this model and leads to very accurate analytical results connecting the three observables: oblateness (ò), gravitational quadrupole (J2), and angular velocity parameter (q). The analytical results are compared to observational data for the planets and a good agreement is found. Oscillations near equilibrium are studied within the model.

Rotational Inertial Physics in Non-Classical Thermoviscous Fluent Continua Incorporating Internal Rotation Rates

In this paper, we derive non-classical continuum theory for physics of compressible and incompressible thermoviscous non-classical fluent continua using the conservation and balance laws (CBL) by incorporating additional physics of internal rotation rates arising from the velocity gradient tensor as well as their time varying rates and the rotational inertial effects. In this non-classical continuum theory time dependent deformation of fluent continua results in time varying rotation rates i.e., angular velocities and angular accelerations at material points. Resistance offered to these by deforming fluent continua results in additional moments, angular momenta and inertial effects due to rotation rates i.e., angular velocities and angular accelerations at the material points. Currently, this physics due to internal rotation rates and inertial effects is neither considered in classical continuum mechanics (CCM) nor in non-classical continuum mechanics (NCCM). In this paper, we present a derivation of conservation and balance laws in Eulerian description: conservation of mass (CM), balance of linear momenta (BLM), balance of angular momenta (BAM), balance of moment of moments (BMM), first and second laws of thermodynamics (FLT, SLT) that include: (i) Physics of internal rotation rates resulting from the velocity gradient tensor;(ii) New physics resulting due to angular velocities and angular accelerations due to spatially varying and time dependent rotation rates. The balance laws derived here are compared with those that only consider the rotational rates but neglect rotational inertial effects and angular accelerations to demonstrate the influence of the new physics. Constitutive variables and their argument tensors are established using conjugate pairs in the entropy inequality, additional desired physics and principle of equipresence when appropriate. Constitutive theories are derived using Helmholtz free energy density as well as representation theorem and integrity (complete basis). It is shown that the mathematical model consisting of the conservation and balance laws and constitutive theories presented in this paper has closure. Influence of new physics in the conservation and balance laws on compressible and incompressible thermoviscous fluent continua is demonstrated due to presence of angular velocities and angular accelerations arising from time varying rotation rates when the deforming fluent continua offer rotational inertial resistance. The fluent continua are considered homogeneous and isotropic. Model problem studies are considered in a follow-up paper.

基于瞬时角速度信号窄带解调的RV减速器针齿故障检测

针对工业机器人实际工况下旋转矢量(rotary vector,RV)减速器低速级不完全旋转工况针齿故障特征提取困难的问题,研究结合编码器信号的优势,提出一种基于瞬时角速度(instantaneous angular speed,IAS)信号窄带解调的RV减速器针齿故障检测方法。首先,消除RV减速器换向过程产生的异常数据,获取非整周转RV减速器的IAS信号;接着,对IAS信号进行角域同步平均,消除非同步干扰对信号分析的影响;随后,设计带通滤波器对信号进行滤波;最后,通过幅值解调和相位解调进行针齿故障检测。试验结果显示,所提方法可有效实现RV减速器低速级不完全旋转工况下的针齿故障检测。

一种未知转速下的RV减速器故障诊断方法

随着制造业的快速发展,工业机器人已经成为智能制造的核心执行单元。针对旋转矢量(Rotary vector,RV)减速器在运行过程中转速时变、瞬时转速不易被读取的问题,提出一种基于电流信号和振动信号的RV减速器健康状态评估方法。基于电流信号的瞬时频率获取输入转频信息,计算得出减速器组成部件的故障特征频率;同步截取平稳振动信号,再利用粒子寻优的变分模态分解算法对提取出来的振动特征进行分解,并基于多维评价函数选取故障敏感分量进行包络分析,以挖掘故障信息进而评估其健康状态。最后,通过实验数据集验证该方法的有效性。结果表明,本文所提方法可以获得工业机器人在作业时的关节输入转速,同时,多维评价函数可以从RV减速器信号中提取富含冲击信息的故障敏感分量。

RV减速器静态回差分析及误差分配研究

以旋转矢量（rotate vector，RV）减速器为研究对象，分析了RV减速器静态回差的影响因素，建立了矩阵形式的静态回差分析数学模型，并推导出了针齿中心圆半径误差等15项误差的误差分配数学模型．以CSRV-160E-171型减速器为实例进行了误差分配计算，并基于误差分配结果进行PROE三维建模，建立了包含15项误差的虚拟样机模型1、模型2以分别模拟静态回差上、下限．建立了基于ADAMS的RV减速器回差仿真分析模型，提出了静态回差测试方案．仿真得出回差值为0．18′-1．19′，与设计值相似．仿真结果证明了误差分配数学模型的正确性．

RV减速器扭转振动的固有特性及灵敏度分析

以RV减速器为研究对象,综合考虑系统刚度和摆线轮偏心角度对扭转振动特性的影响,采用集中参数法,建立了该系统13个自由度的修正扭转动力学模型。通过求解自由振动方程得到系统固有频率及主振型,分析了摆线轮偏心角度对系统固有频率的影响。利用偏导数法分析了系统固有频率对转动惯量和刚度的影响。研究结果表明,轴承刚度为系统固有频率的关键影响因素。

RV传动机构精度分析

以一类含渐开线和摆线的二级封闭式行星传动机构即RV(rotate vector)机构为对象,基于作用线增量原理,应用误差分析的传递矩阵法,研究了机构中各构件的原始误差在整个传动过程中对机构输出转角误差的影响规律,建立了适用于该机构精度分析的误差模型.该模型建立了各构件原始误差与机构输出误差的解析对应关系,揭示了机构中共用构件(曲柄轴等)的误差传递过程,以及由于固连输出盘与系杆导致的机构反馈误差与各构件原始误差的耦合关系,为该类机构的精度分析与设计提供了可靠的理论依据.最后,以RV320S型减速器为例,进行实例验算.结果表明,对机构输出转角误差影响最大的是输出盘上曲柄轴孔偏心误差,其次是摆线轮齿廓误差;机构的反馈误差对于高精密RV传动系统也不应忽视.

主要误差因素对RV减速器的传动特性影响研究

采用SolidWorks对RV减速器建立含有给定误差的参数化模型,然后导入ADAMS中,使用宏程序批量建立动力学模型并仿真分析,将输出的转速与转角数据导入Matlab中,数据处理后,计算传动误差并用输出转速的方差来衡量转速波动值的大小。仿真结果表明,在给定误差值改变量相同的情况下,减小针齿半径和增大正等距修形量,转速波动值明显增大;增大负等距和负移距修形量时,转速波动值会有所减小;减小针齿半径和增大正等距修形量的值,传动误差会明显增大,增大针轮偏心值对传动误差影响不大。

RV减速器转臂轴承的优化设计

为延长RV减速器疲劳寿命,利用遗传算法对RV减速器转臂轴承进行了设计优化。设定基本额定动载荷为目标函数,以轴承节圆直径、滚子直径、滚子数量、滚子有效接触长度为设计变量,从几何、强度、润滑和摩擦方面给出约束,并对优化结果进行灵敏度分析。优化结果表明,优化设计方法可以有效提高RV减速器的疲劳寿命。

考虑摆线轮磨损的RV减速器传动精度可靠性分析与参数优化

针对RV (rotate vector)减速器在工作过程中存在的零件磨损导致传动精度下降的问题,建立了考虑摆线轮磨损的RV减速器传动精度动态可靠性模型,进行传动精度可靠性分析,并对关键零件的公差以及摆线轮的修形参数进行优化设计。以某重载RV减速器为研究对象,利用Archard磨损公式对摆线轮的磨损深度进行计算,分析轮齿齿廓磨损的分布情况,并基于数值仿真数据利用高斯过程回归模型预测磨损量;建立了含动态磨损的RV减速器传动精度可靠性模型,用蒙特卡洛法求解其动态可靠度;建立了以传动精度动态可靠度为约束条件,以加工成本最低、额定寿命周期内最大磨损量最小为优化目标的优化模型,采用多目标遗传算法求得最优解。结果表明;优化后摆线轮的磨损量略微增大,而减速器的加工成本明显降低;优化后减速器传动精度可靠度得到明显提高,在额定寿命6 000 h内的可靠度满足预期要求。研究结果可以为高精度RV减速器的设计提供参考。

基于经验模态分解的RV减速器运动参数降噪研究

RV(rotate vector)减速器是现代智能装备中关键传动机构之一,其运动参数的检测信号噪声成分较高,影响了装备的运行精度和稳定性,提出了一种以经验模态分解(empirical mode decomposition,EMD)为基础的信号降噪方法,有效提取了RV减速器运动参数的准确信号。该方法采用连续均方误差(consecutive mean square error,CMSE)和l 2范数两个指标将EMD分解得到的固有模态函数(intrinsic mode function,IMF)区分为噪声IMF、噪声与信息相混合IMF、信息IMF 3个部分,采用不同策略对这三部分IMF进行处理并结合部分重构(part reconstruction,PR)策略实现了信号的降噪处理。采用该文章提出的降噪方法对RV40E减速器的检测信号进行处理,降噪后的信号信噪比得到明显改善,验证了该降噪方法的有效性。