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本文首先给出广义扭仿射李代数的概念;然后讨论这种李代数的不可约模H的性质;特别是给出了H的一个自然阶化分解;通过研究扭李代数g的流表示,证明关于扭流的换位关系式;最后证明作用在不可约模上的一类算子的局部幂零性.这一结果对研究共形块空间的广义扭仿射李代数模的实现起着基本的作用. 相似文献
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符渠雷 《数学年刊A辑(中文版)》2022,43(1):95-102
假设有限群上的块b被其亏群的正规化子控制,其超聚焦子群是16阶的初等交换群并且包含在亏群的中心里.本文计算了部分情况下块b的不可约模特征标和不可约常特征标个数.在这些情况下,Alperin重量猜想是对的. 相似文献
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流道插件(FCI)是ITER中包层模块的重要部件,起到电绝缘和热绝缘的作用,FCI的力学行为是对复杂的磁-热-流-固多物理场共同作用的响应.将有限体积法和有限元方法相结合,对包层流道中的流场、温度场以及FCI的应力应变场进行求解,分析了磁场效应对结构的影响,以及不同FCI壁厚和间隙流宽度等结构特征对包层的影响.计算结果表明,强磁场虽然会产生较强的MHD效应,但可以降低第一壁温度和FCI结构热应力;较厚的FCI可以降低第一壁上的最高温度,但也会增加FCI上的温度梯度和热应力;而较宽的间隙有利于降低第一壁上的最高温度,但会增加FCI的最大Mises应力. 相似文献
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针对矩形边界越流承压含水层中非完整井抽水引起的复杂地下水流动问题,建立了直角坐标系下越流承压含水层非完整井稳定流数学模型.通过对地下水流动计算模型的有限Fourier变换和有限Fourier变换域降深函数的逆变换,提出了不同类型边界条件下越流承压含水层非完整井三维稳定流降深解析解.在验证降深解析解正确性的基础上,通过降深解析解计算精度的分析,并结合非完整井抽水条件下含水层地下水流动特性,给出了降深解析解满足计算精度要求的计算项数取值.探讨了含水层正交各向异性、抽水井完整性、井位布置等因素对含水层降深和地下水流动的影响规律,并利用工程案例阐明了降深解析解的工程适用性. 相似文献
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《数学物理学报(A辑)》2017,(4)
同轴圆筒间旋转流动的Couette-Taylor流问题是近一个世纪以来人们普遍关注的热点问题,由于其流动形态的可观测性以及它在湍流研究中的基础性地位及其在流体机械、石油化工等领域的广泛应用,国际上将其列为非线性科学的范例之一.为了探讨这种流动从层流到湍流过渡的方式以及流动发展到湍流之后混沌吸引子的某些特征等问题,该文采用低模分析方法研究了Couette-Taylor流的部分动力学行为及仿真问题,探讨了同轴圆筒间Couette-Taylor流三模态类Lorenz型方程组的动力学行为及仿真问题,数值模拟了系统分岔与混沌的演变历程,讨论了系统的全局稳定性. 相似文献
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定义了子空间格代数的(弱闭双边)模,对有限维Hilbert空间的强自反子空间格代数的模及原子Boolean格代数的模中的有限秩算子进行了讨论,得到有限秩算子一定可以表示为秩1算子的和. 相似文献
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Brauer图对于刻画有限群的p-块是非常关键的.高零不可约(复)特征标在有限群模表示理论中的Brauer图中扮演着重要的角色.本文用若干例子阐述了关于高零不可约特征标的几个问题. 相似文献
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为克服涡旋法不能精确预计物体附近小尺度流动结构的理论缺陷,减少高Reynolds数流动N-S方程差分解的困难,本文提出一种区域分解、杂交耦合N-S方程有限差分解及涡旋法的新的数值模型和理论方法.将流场分解为内外两区,在靠近物体表面、范围为O(R)的内区进行N-S方程有限差分解,外区作Lagrange-Euler涡旋法解,建立了分区流动的联结、耦合条件,给出了杂交耦合求解的数值计算方法.用本方法作了Re=102,103的圆柱绕流计算,考察了区域交界面位置变化时解的稳定性.与全场N-S方程解及实验结果的比较表明本文方法能精确预计流动分离及近场流动的详细结构,并可有效地计算流动的总体特性,且比全场N-S方程解显著节省机时和计算量. 相似文献
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N. V. Tyabin V. G. Bortnikov E. M. Tsentovskii K. D. Vachagin 《Mechanics of Composite Materials》1968,4(3):416-420
The flow of a non-Newtonian fluid in an annular extruder channel formed by two coaxial cylinders is investigated theoretically. Complex shear conditions are created by the pressure difference between the ends of the channel and the rotation of the cylinders in opposite directions at constant speeds. An expression is obtained for the rate of flow of a polymer melt regarded as a non-Newtonian fluid. The flow of a polyethylene melt at 140° C through an extruder head with a rotating mandrel has been experimentally investigated. The experimental data serve to confirm the theoretical conclusions.Mekhanika Polimerov, Vol. 4, No. 3, pp. 531–539, 1968 相似文献
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The unsteady flow of a viscous incompressible gas embedded with small spherical particles in a rectangular channel is studied. The flow is produced under the influence of an arbitrary time varying pressure gradient. The exact velocities of the gas and particles are obtained by operational methods. The change in velocity profiles of the gas and particles with time for a constant pressure gradient, have been drawn graphically. It is found that the velocities of the gas and particles are maximum in the central plane of the channel. 相似文献
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V. G. Litvinov 《Mechanics of Composite Materials》1968,4(4-6):883-889
The problem of nonrectilinear steady-state flow of a nonlinear viscoelastic liquid in an arbitrary cylindrical channel is examined. On the assumption that the cross flows are insignificant as compared with the longitudinal flows an equation of state is derived for the flow regime in question. A variational principle established for steady-state flows of the investigated media is proposed as the basis of a method of solving problems of the flow of polymer materials in arbitrary cylindrical channels. The flow of a polymer solution in rectangular channels is investigated.Institute of Mechanics, AS UkrSSR, Kiev. Translated from Mekhanika Polimerov, Vol. 4, No. 6, pp. 1103–1111, November–December, 1968. 相似文献
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The paper describes results of a numerical simulations of air flow in a turned off, 2D channel with the plain nozzle. Simulations are based on an earlier experiment, carried out by Dyban, Mazur and Epik (1971). In the featured channel it has been observed several bifurcation forms, depending on the flow velocity and geometry relations. Basing on the numerical simulations results, the integral characteristics of the flow areas has also been presented. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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本文考虑的问题是二维粘性渠流。对0到2000之间的雷诺数,计算了平稳扰动的Couette-Poiseuille流的下游特征值,其特征方程类似于Orr-Sommerfeld方程。所用的方法是谱方法和初值方法(复合矩阵方法).就几种有趣的流量,给出了相应的特征值的计算结果。这些特征值确定了扰动的衰减率。 相似文献
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纬向对称准地转流的非线性稳定性定理 总被引:4,自引:0,他引:4
建立了周期域上准地转流在一般的边界条件下对应于Arnold第二定理的非线性稳定性定理。将扰动能量与扰动拟能的上界用初始扰动场的显示表示出来,从而建立了Liapunov意义下的非线性稳定性定理。 相似文献
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Modelling of rotating turbulent flows is a major issue in engineering applications. Intensive research has been dedicated to rotating channel flows in spanwise direction such as by [1], [2] to name only two. In this work a turbulent channel flow rotating about the streamwise direction is presented. The theory is based on the investigations of [4] employing the symmetry theory. It was found that a cross flow in the spanwise direction is induced. A series of direct numerical simulations (DNS) at different rotation numbers is carried out to examine these effects. Further, the results of the DNS are compared to the measuremets of a corresponding experiment. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献