共查询到20条相似文献,搜索用时 765 毫秒
1.
《Communications in Nonlinear Science & Numerical Simulation》2010,15(9):2407-2423
Magnetohydrodynamic (MHD) peristaltic flow of a Carreau fluid in a channel with different wave forms are analyzed in this investigation. The flow analysis is conducted in the presence of an induced magnetic field. Long wavelength approach is adopted. Mathematical expressions of stream function, magnetic force function and an axial induced magnetic field are constructed. Pressure rise and pumping phenomena are described. 相似文献
2.
T. Hayat Yasir Khan Kh. S. Mekheimer Nasir Ali 《Numerical Methods for Partial Differential Equations》2010,26(2):345-366
In this article, we carry out the effect of an induced magnetic field on the peristaltic transport of an incompressible conducting third order fluid in a symmetric channel. The flow analysis has been developed for low Reynolds number and long wave length approximation. Analytical solutions have been established for the axial velocity, stream function, magnetic force function, and axial‐induced magnetic field. The effects of pertinent parameters on the pressure rise per wavelength are investigated by using numerical integration. Besides this, we study the effect of these parameters on the pressure gradient and axial induced magnetic field. The phenomena of trapping and pumping are also discussed. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2010 相似文献
3.
Y. Abd elmaboud 《Communications in Nonlinear Science & Numerical Simulation》2012,17(2):685-698
This paper looks at the influence of the induced magnetic field on peristaltic transport through a uniform infinite annulus filled with an incompressible viscous and Newtonian fluid. The present theoretical model may be considered as mathematical representation to the movement of conductive physiological fluids in the presence of the endoscope tube (or catheter tube). The inner tube is uniform, rigid, while the outer tube has a sinusoidal wave traveling down its wall. The flow analysis has been developed for low Reynolds number and long wave length approximation. Exact solutions have been established for the axial velocity, stream function, axial induced magnetic field, current distribution and the magnetic force function. The effects of pertinent parameters on the pressure rise and frictional forces on the inner and outer tubes are investigated by means of numerical integrations, also we study the effect of these parameters on the pressure gradient, axial induced magnetic field and current distribution. The phenomena of trapping is further discussed. 相似文献
4.
V. R. Khalilov 《Theoretical and Mathematical Physics》2000,125(1):1413-1430
The Green's function of the Dirac equation with an external stationary homogeneous magnetic field in the (2+1)-dimensional
quantum electrodynamics (QED
2+1) with a nonzero fermion density is constructed. An expression for the polarization operator in an external stationary homogenous
magnetic field with a nonzero chemical potential is derived in the one-loopQED
2+1 approximation. The contribution of the induced Chern—Simons term to the polarization operator and the effective Lagrangian
for the fermion density corresponding to the occupation of n relativistic Landau levels in an external magnetic field are
calculated. An expression of the induced Chern—Simons term in a magnetic field for the case of a finite temperature and a
nonzero chemical potential is obtained.
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 125, No. 1, pp. 132–151, October, 2000. 相似文献
5.
The induced magnetic field produced by a circular polarization laser pulse propagating in a cold plasma, and the dynamics of injected electron in the combination field of the laser field and the induced magnetic field are investigated. As a circular polarization laser propagates in a plasma, a quasistatic magnetic field in the direction of the wave propagation is rising. An evolution equation for the induced magnetic field is derived. Based on the derived equation, the properties of the induced magnetic field are discussed. The injected electron which satisfies the cyclotron resonance condition can be accelerated by the combination field. The energy equation for the injected electron is obtained. Finally, the classical dynamics of the injected electron in the combination field is analyzed. 相似文献
6.
在横向磁场作用下,研究Hall电流对竖直可渗透平板上MHD自然对流的影响,平板具有均匀的热通量.和外部磁场相比,假设感应磁场可以忽略不计.利用自由变量公式化(FVF)和流函数公式化(SFF),将边界层方程简化为适当的形式.对局部蒸发系数ζ的整个取值范围,由FVF得到的抛物型方程,用简明的有限差分法进行数值积分;另一方面,由SFF得到的非相似方程,采用局部非相似法求解.有些区域,如局部蒸发系数ζ值足够大或足够小时,用正规的摄动法求解.对低值Prandtl数Pr,例如Pr=0.005,0.01,0.05时,用图形表示磁场参数M和Hall参数m,对局部表面摩擦因数和局部Nusselt数的影响.最后对不同的局部蒸发系数ζ值,给出流体的速度和温度分布. 相似文献
7.
I. Pop 《Proceedings Mathematical Sciences》1973,78(6):231-238
The flow of an electrically conducting incompressible viscous fluid near an infinite flat wall in the presence of a magnetic field when the free stream velocity is to be expressed in power series of √ t is considered. The effect of the magnetic field strength on the velocity field induced magnetic field and skin friction is analyzed for two particular cases of the free stream velocity. 相似文献
8.
The aim of this letter is to construct the analytic solution for unsteady Couette flow in the presence of an arbitrary non-uniform applied magnetic field. The flow is induced by a generalized velocity given to the lower plate. The perturbed eigenfunction expansion method is employed to develop a series solution for small magnetic field. 相似文献
9.
A new model of the equations of generalized thermovisco-elasticity for a thermally, isotropic and electrically conducting half-space solid whose surface is subjected to a thermal shock is given. The formulation is applied to the generalized thermoelasticity based on the Green and Lindsay (GL) theory under the effect of rotation, where there is an initial magnetic field parallel to the plane boundary of the half-space. The medium is deformed because of thermal shock and due to the application of the magnetic field, it results an induced magnetic and electric fields in the medium. The normal mode analysis is used to obtain the expressions for the variables considered. The distributions of temperature, displacement, stress, induced magnetic and electric fields are represented graphically. Comparisons are made with the results predicted by the coupled theory (CD) in the presence and absence of rotation. 相似文献
10.
N. M. Bujurke 《Proceedings Mathematical Sciences》1979,88(2):147-156
Stoke's classic problem involving the impulsive motion of an infinite flat plate in an unbounded viscous incompressible fluid is investigated under the additional specification that the fluid is electrically conducting and the motion is developed in the presence of uniform transverse magnetic field. For the fluids with arbitrary magnetic Prandtl number, the compact expression for the skin friction coefficient at the plate is given in terms of exponential and error functions of complex arguments. For the fluids with unit magnetic Prandtl number, expressions for the induced magnetic field, velocity, current density and induced electric field in the viscous boundary layer region set up near the plate are obtained. The effect of the magnetic field on the skin friction is to make it approach the steady state faster than in nonmagnetic case. 相似文献
11.
12.
We study magnetohydrodynamic flow of a liquid metal in a straight duct. The magnetic field is produced by an exterior magnetic dipole. This basic configuration is of fundamental interest for Lorentz force velocimetry (LFV), where the Lorentz force opposing the relative motion of conducting medium and magnetic field is measured to determine the flow velocity. The Lorentz force acts in equal strength but opposite direction on the flow as well as on the dipole. We are interested in the dependence of the velocity on the flow rate and on strength of the magnetic field as well as on geometric parameters such as distance and position of the dipole relative to the duct. To this end, we perform numerical simulations with an accurate finite-difference method in the limit of small magnetic Reynolds number, whereby the induced magnetic field is assumed to be small compared with the external applied field. The hydrodynamic Reynolds number is also assumed to be small so that the flow remains laminar. The simulations allow us to quantify the magnetic obstacle effect as a potential complication for local flow measurement with LFV. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
13.
14.
D. Yarımpabuç H.I. Tarman C. Yıldırım 《Mathematical Methods in the Applied Sciences》2014,37(18):2962-2971
The effect of an inclined homogeneous magnetic field on thermal convection between rigid plates heated from below under the influence of gravity is numerically simulated in a computational domain with periodic horizontal extent. The numerical technique is based on solenoidal (divergence‐free) basis functions satisfying the boundary conditions for both the velocity and the induced magnetic field. Thus, the divergence‐free conditions for both velocity and magnetic field are satisfied exactly. The expansion bases for the thermal field are also constructed to satisfy the boundary conditions. The governing partial differential equations are reduced to a system of ordinary differential equations under Galerkin projection and subsequently integrated in time numerically. The projection is performed by using a dual solenoidal bases set such that the pressure term is eliminated in the process. The quasi‐steady relationship between the velocity and the induced magnetic field corresponding to the liquid metals or melts is used to generate the solenoidal bases for the magnetic field from those for the velocity field. The technique is validated in the linear case for both oblique and vertical case by reproducing the marginal stability curves for varying Chandrasekhar number. Some numerical simulations are performed for either case in the nonlinear regime for Prandtl numbers Pr = 0.05 and Pr = 0.1. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
15.
K. D. Singh 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2004,55(5):894-902
A three dimensional steady fully developed MHD Couette flow of a viscous incompressible electrically conducting fluid is analysed. The lower stationary porous plate is subjected to a periodic injection velocity and the upper porous plate in uniform motion to a constant suction velocity. A magnetic field of uniform strength applied normal to the planes of the plates is fixed with the moving plate. Neglecting the induced magnetic field, an approximate solution for the flow field is obtained and discussed with the help of graphs. 相似文献
16.
K. D. Singh 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2004,98(2):894-902
A three dimensional steady fully developed MHD Couette flow of a viscous incompressible electrically conducting fluid is analysed. The lower stationary porous plate is subjected to a periodic injection velocity and the upper porous plate in uniform motion to a constant suction velocity. A magnetic field of uniform strength applied normal to the planes of the plates is fixed with the moving plate. Neglecting the induced magnetic field, an approximate solution for the flow field is obtained and discussed with the help of graphs. 相似文献
17.
Yu. N. Podil'chuk 《Journal of Mathematical Sciences》2001,103(3):287-295
The stressed-deformed state of an unbounded isotropic body consisting of a magnetically soft ferromagnetic material and containing a parabolic crack is examined. It is assumed that the body is acted on by an external magnetic field perpendicular to the plane of the crack. The major characteristics of the stressed-deformed state and the induced magnetic field are determined and their features near the parabolic crack are studied. Formulas are given for determining the stress intensity factors for the mechanical force and magnetic fields at the crack vertex. 相似文献
18.
Carsten Mayer 《Journal of Fourier Analysis and Applications》2006,12(4):345-369
This article is concerned with an approach of modelling the Earth’s magnetic field as measured by satellites in terms of a
special system of vector spherical harmonics and in terms of vector kernel functions, called vector scaling functions and
wavelets. The main ingredient is the presentation of a system of vector spherical harmonics which separates a given spherical
vector field with respect to its sources, i.e., the spherical vector field is separated into a part which is induced by sources
inside the sphere, a part which is induced by sources outside the sphere and a part which is induced by sources on the sphere,
which are, for example, currents crossing the sphere. Using this special system of vector spherical harmonics vector scaling
functions and wavelets are constructed which keep the advantageous property of separating with respect to sources but which
also allow a locally reflected modelling of the respective vector field. At the end of the article, the method is tested on
real magnetic field data measured by the German geoscientific research satellite CHAMP. 相似文献
19.
K. D. Singh 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1990,41(3):441-446
Hydromagnetic effects on the three-dimensional flow of an electrically conducting viscous incompressible fluid past a porous plate with periodic suction has been analysed. The uniform flow is subjected to a transversely applied magnetic field. The mathematical analysis is presented for the hydromagnetic boundary layer flow neglecting the induced magnetic field. Approximate solutions for the components of velocity field and the skin-frictions due to them are obtained and discussed with the help of a graph and tables. 相似文献
20.
Reconstruction of biologic tissue conductivity from noisy magnetic field by integral equation method
Magnetic resonance electrical impedance tomography (MREIT) is a new technique to recover the conductivity of biologic tissue from the induced magnetic flux density. This paper proposes an inversion scheme for recovering the conductivity from one component of the magnetic field based on the nonlinear integral equation method. To apply magnetic fields corresponding to two incoherent injected currents, an alternative iteration scheme is proposed to update the conductivity. For each magnetic field, the regularizing technique on the finite dimensional space is applied to solve an ill-posed linear system. Compared with the well-developed harmonic Bz method, the advantage of this inversion scheme is its stability, since no differential operation is required on the noisy magnetic field. Numerical implementations are given to show the convergence of the iteration and its validity for noisy input data. 相似文献