• Title/Summary/Keyword: micropolar fluid

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A Similarity Solution of the Characteristics of Micropolar Fluid Flow in the Vicinity of a Wedge (상사해법을 이용한 쐐기형 물체 주위의 미세 극성유체 유동 특성에 관한 연구)

  • Kim, Youn J.
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.23 no.8
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    • pp.969-977
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    • 1999
  • A similarity solution of a steady laminar flow of micropolar fluids past wedges has been studied. The similarity variables found by Falkner and Skan are employed to reduce the streamwise-dependence in the coupled nonlinear boundary layer equations. Numerical solutions of the equations are then obtained using the fourth-order Runge-Kutta method and the distribution of velocity, micro-rotation, shear and couple stress across the boundary layer are obtained. These results are compared with the corresponding flow problems for Newtonian fluid past wedges with various wedge angles. Numerical results show that, keeping ${\beta}$ constant, the skin friction coefficient is lower for a micropolar fluid, as compared to a Newtonian fluid. For the case of constant material parameter K, however, the velocity distribution for a micropolar fluid is higher than that of a Newtonian fluid.

Analysis of Microchannel Flow Fields Using Micropolar Fluid Theory (미세극성유체 이론을 이용한 마이크로 채널내의 유동장 해석)

  • Choi, G.W.;Kim, J.H.;Kim, Youn-J.
    • Proceedings of the KSME Conference
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    • 2001.06e
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    • pp.196-201
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    • 2001
  • In this paper, we have described the microchannel fluid behavior in a slot between rotating curvilinear surfaces of revolution using micropolar fluid theory. ]n order to solve this problem, we have used boundary layer equations and applied non-zero values of the microrotation vector on the wall. The results are compared with the corresponding flow problems for Newtonian fluid. Results show that both the velocity distribution and the microrotation component distribution for a micropolar fluid are lower than that of a Newtonian fluid.

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A Study on the Thermal Boundary Layer Flow of a Micropolar Fluid in the Vicinity of a Wedge (미세극성 유체 유동장에 놓여진 쐐기형 물체주위의 열경계층에 관한 연구)

  • 김윤제
    • The Korean Journal of Rheology
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    • v.11 no.2
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    • pp.122-127
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    • 1999
  • The characteristics of thermal boundary layer flow of a micropolar fluid in the vicinity of a wedge has been studied with constant surface temperature. The similarity variables found by Falkner and Skan are employed to reduce the streamwise-dependence in the coupled nonlinear boundary layer equations. Numerical solutions are presented for the heat transfer characteristics with Pr=1 using the fourth-order Runge-Kutta method and their dependence on the material parameters is discussed. The distributions of dimensionless temperature and Nusselt number across the boundary layer are compared with the corresponding flow problems for a Newtonian fluid over wedges. Numerical results show that for a constant wedge angle with a given Prandtl number, Pr=1, the effect of increasing values of K results in an increasing thermal boundary thickness for a micropolar fluid, as compared with a Newtonian fluid. For the case of the constant material parameter K, however, the heat transfer rate for a micropolar fluid is lower than that of a Newtonian fluid.

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A Study on the Plane Couette Flow Using Micropolar Fluid Theory

  • Kim, Youn-Jea;Kim, Tae-An
    • Journal of Mechanical Science and Technology
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    • v.18 no.3
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    • pp.491-498
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    • 2004
  • An analysis of the plane Couette flow between two parallel plates of a viscous, incompressible, micropolar fluid is presented. Especially, the effects of non-zero values of the micro-gyration boundary condition coefficient and pressure gradient on the flow fields are studied. Numerical results show that the micro polar parameter was found to have much more of an impact on the flow behaviors. It is also observed that the micro-gyration boundary condition coefficient influenced on the coefficients of skin friction and couple stress due to its different effect on the surface stress.

ON MIXED PRESSURE-VELOCITY REGULARITY CRITERIA FOR THE 3D MICROPOLAR EQUATIONS IN LORENTZ SPACES

  • Kim, Jae-Myoung;Kim, Jaewoo
    • Journal of the Chungcheong Mathematical Society
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    • v.34 no.1
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    • pp.85-92
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    • 2021
  • In present paper, inspired by the recently paper [1], we give the mixed pressure-velocity regular criteria in view of Lorentz spaces for weak solutions to 3D micropolar equations in a half space. Precisely, if (0.1) ${\frac{P}{(e^{-{\mid}x{\mid}^2}+{\mid}u{\mid})^{\theta}}{\in}L^p(0,T;L^{q,{\infty}}({\mathbb{R}}^3_+))$, p, q < ∞, and (0.2) ${\frac{2}{p}}+{\frac{3}{q}}=2-{\theta}$, 0 ≤ θ ≤ 1, then (u, w) is regular on (0, T].

AN ELECTROMAGNETIC FREE CONVECTION FLOW OF A MICROPOLAR FLUID WITH RELAXATION TIME

  • Zakaria, M.
    • Journal of applied mathematics & informatics
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    • v.8 no.2
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    • pp.539-550
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    • 2001
  • In the present investigation, we study the influence of a transverse magnetic field through a porous medium. Laplace transform techniques are used to derive the solution in the Laplace transform domain. The inversion process is carried out using a numerical method based on Fourier series expansions. Numerical computations for the temperature, the microrotation and the velocity distributions as well as for the induced magnetic and electric fields and carried out and represented graphically.

Hall and Ion-Slip effects on magneto-micropolar fluid with combined forced and free convection in boundary layer flow over a horizontal plate

  • Seddeek, M.A.;Abdelmeguid, M.S.
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.8 no.2
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    • pp.51-73
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    • 2004
  • A boundary layer analysis is used to study the effects of Hall and ion-slip currents on the steady magneto-micropolar of a viscous incompressible and electrically conducting fluid over a horizontal plate. By means of similarity solutions, deviation of fundamental equations on the assumption of small magnetic Reynolds number are solved numerically by using the shooting method. The effects of various parameters of the problem, e.g. the magnetic parameter, Hall parameter, ion-slip parameter, buoyancy parameter and material parameter are discussed and shown graphically.

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INFLUENCE OF THERMAL CONDUCTIVITY AND VARIABLE VISCOSITY ON THE FLOW OF A MICROPOLAR FLUID PAST A CONTINUOUSLY MOVING PLATE WITH SUCTION OR INJECTION

  • Salem, A.M.;Odda, S.N.
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.9 no.2
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    • pp.45-53
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    • 2005
  • This paper investigates the influence of thermal conductivity and variable viscosity on the problem of micropolar fluid in the presence of suction or injection. The fluid viscosity is assumed to vary as an exponential function of temperature and the thermal conductivity is assumed to vary as a linear function of temperature. The governing fundamental equations are approximated by a system of nonlinear ordinary differential equations and are solved numerically by using shooting method. Numerical results are presented for the distribution of velocity, microrotation and temperature profiles within the boundary layer. Results for the details of the velocity, angular velocity and temperature fields as well as the friction coefficient, couple stress and heat transfer rate have been presented.

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Effects of Vortex Viscosity Variation on the Flowfields in a Micro-slot between Rotating Surfaces of Revolution (와점성 변화가 회전곡면으로 이루어진 마이크로 슬롯 유동장에 미치는 영향)

  • Choi, G.W.;Kim, Youn-J.
    • Proceedings of the KSME Conference
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    • 2001.11b
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    • pp.591-596
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    • 2001
  • Micron-size mechanical devices are becoming more prevalent, both in commercial applications and in scientific inquiry. Within the last decade, a dramatic increase in research activities has taken place, mostly due to the rapidly expanding growth of applications in areas of MEMS(Micro-Electro-Mechanical Systems), bioengineering, chemical systems, and advanced energy systems. In this study, we have described the effects of vortex viscosity variation on the flowfields in a micro-slot between rotating surfaces of revolution using a micropolar fluid theory. In order to solve this problem, we have used boundary layer equations and applied non-zero values of the microrotation vector on the wall. The results are compared with the corresponding flow problems for Newtonian fluid. Results show that the coefficient $\delta$ controls the main part of velocity ${\upsilon}_x$ and the coefficient M controls the main part of microrotation component ${\Omega}_{\theta}$.

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