NUMERICAL ANALYSIS OF HYDROMAGNETIC GRAVITY-DRIVEN THIN FILM MICROPOLAR FLOW ALONG AN INCLINED PLANE

The steady, gravity-driven, incompressible, hydromagnetic, laminar flow of a viscous, electrically conducting, micropolar liquid along an inclined plane subjected to a uniform transverse magnetic field is examined, neglecting surface tension effects. The governing two-dimensional boundary layer equations in an (x, y) coordinate in the absence of pressure gradient are reduced to a pair of ordinary differential equations for linear momentum and angular momentum conservation subject to generalized micro-rotation and velocity boundary conditions at the plane surface. The film thickness is assumed uniform along the plane. The reduced conservation equations are then nondimensionalized and solved numerically with the network simulation method (NSM) and Sparrow-Quack-Boerner local non-similarity method (LNM) for a wide range of the governing dimensionless fluid dynamics parameters. Excellent agreement is obtained between the NSM and LNM solutions. The computations indicate that increasing micropolarity, i.e., Eringen number, elevates micro-rotation magnitudes but reduces linear velocity, i.e., decelerates the flow. The study has significant applications in magnetic field control of materials processing systems.     

The effect of Joule heating and viscous dissipation on the boundary layer flow of a magnetohydrodynamics micropolar-nanofluid over a stretching vertical Riga plate

Joule heating and viscous dissipation effects on the behavior of the boundary layer flow of a micropolar nanofluid over a stretching vertical Riga plate (electro magnetize plate) are considered. The flow is disturbed by an external electric magnetic field. The problem is formulated mathematically by nonlinear system of partial differential equations (PDEs). By using suitable variables transformations, this system is transformed onto a system of nonlinear ordinary differential equations (ODEs). The Parametric NDsolve package of the commercial software Mathematica is used to solve the obtained ODEs as well as the considered numerical results for different physical parameters with appropriate boundary conditions. Novel results are obtained by studying the stream lines flow around the plate in two and three dimensions. Moreover, the effects of the pertinent parameters on the skin friction coefficient, couple stress, local Nusselt, and Sherwood number are discussed. Special cases of the obtained results show excellent agreements with previous works. The results showed that as the magnetic field parameter increases the velocity of the boundary layer adjacent to the stretching sheet decreases. Also, for a productive chemical reaction near the sheet surface, the angular velocity decreases but opposite trend is observed far from the sheet surface. The importance of this study comes from its significant applications in many scientific fields, such as nuclear reactors, industry, medicine, and geophysics.     

金属熔体的电磁成形与凝固

材料的电磁加工是当今材料加工技术领域研究和发展的一个重点。本文简述作为材料电磁加工技术理论基础的电磁流体力学的基本内容，给出电磁场各种的基本原理，着重阐述电磁力和焦耳热在金属熔体电磁成形与凝固过程中的应用。     

多泵磁流体动力学角速度传感器的低频拓展设计研究

针对磁流体动力角速度传感器对低频(＜1 Hz)信号检测性能差的问题,在原有的角速度传感器的基础上提出了一种含多磁流体动力泵的角速度传感器.采用改进传感器机械结构的方法,在流体通道边缘周向上均匀构建多个磁流体动力泵,并优化了流体泵磁极形状,以提高流体传感环中径向流速分布大小与稳定性,增强低频下科里奥利力效应.仿真与实验结...     

Influence of relative motion of magnetic field on time‐dependent MHD natural convection flow

The effects of relative motion of magnetic field on unsteady magnetohydrodynamic free convection flow with ramped motion and temperature‐dependent heat source/sink have been analyzed. The motion of the inner cylinder is ramped while the motion of the outer cylinder is fixed. The momentum and energy equations are solved using the well‐known Laplace transform. The time‐domain solution is obtained using the Riemann‐sum approximation method. The influence of the governing parameters on fluid velocity, fluid temperature, volume flow rate, and rate of heat transfer are discussed with the help of line graphs. It is found that Hartmann number has a retarding effect on fluid velocity, skin friction at the outer surface of the inner cylinder, and mass flow rate when the magnetic field is fixed with the fluid and when the velocity of the magnetic field is less than the velocity of the moving cylinder. Whereas, the reverse effect is noticed when the magnetic field is fixed with the moving cylinder.