• Title/Summary/Keyword: Couette Flow

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Numerical Simulation of Stratified Taylor-Couette Flow (성층화된 Taylor-Couette 유동에 대한 전산해석적 연구)

  • Hwang Jong-Yeon;Yang Kyung-Soo;Kim Dong-Woo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.30 no.7 s.250
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    • pp.630-637
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    • 2006
  • The flow regimes for a Taylor-Couette flow with a stable, axial stratification in density are investigated using numerical simulation. The flow configuration identical to that in the experiment of Boubnov, et al. (1995) is considered in the present research. The main objectives of this investigation are to verify the experimental and numerical results carried out by Boubnov, et al. and Hua et al. (1997), respectively, and to further study the detailed flow fields and flow bifurcations. With increasing buoyancy frequency of the fluid (N), the stratification-dominated flow regime, called the S-regime, is observed. It is also confirmed that the important effect of an axial density stratification is to stabilize the flow field. The present numerical results are in good agreement with Boubnov, et al. and Hua et al.'s observations.

Elastically-influenced instabilities in Taylor-Couette and other flows with curved streamlines: a review

  • Muller, Susan J.
    • Korea-Australia Rheology Journal
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    • v.20 no.3
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    • pp.117-125
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    • 2008
  • Viscoelastic instabilities are of fundamental importance to understanding the physics of complex fluids and of practical importance to materials processing and fluid characterization. Significant progress has been made over the past 15 years in understanding instabilities in viscoelastic flows with curved streamlines and is reviewed here. Taylor-Couette flow, torsional flow between a cone and plate, and torsional flow between parallel plates have received special attention due to both the basic significance of these flows and their critical role in rheometry. First, we review the criteria for determining when these flows become unstable due to elasticity in the absence of inertia, and discuss the generalization of these criteria to more complex flows with curved streamlines. Then, focusing on experiments and simulations in the Taylor-Couette problem, we review how thermal sensitivity (i.e., the dependence of fluid viscosity and elasticity on temperature) and inertia affect the stability of viscoelastic flows. Finally, we conclude with some general thoughts on unresolved issues and remaining challenges related to viscoelastic instabilities.

Experimental study of the Concentric Cylinder Flow with Various Axial Slit Wall (다양한 축방향 홈이 있는 동심원통 내부 유동에 대한 실험적 연구)

  • Lee, Sang-Hyuk;Kim, Hyoung-Bum
    • 한국가시화정보학회:학술대회논문집
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    • 2007.11a
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    • pp.123-127
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    • 2007
  • The effect of axial slit wall of outer cylinder on Taylor-Couette flow was experimentally investigated. The axial slits were azimuthally located along the inner wall of outer cylinder and the number of slits was 6, 9 and 18. The radius ratio and aspect ratio of the experimental models was 0.825 and 48, respectively. We used PIV method to measure the flow field and applied refractive index matching method to resolve the image distortion due to the complex model geometry. The results showed the effect of slit on the flow transition is increased as the number of slit increased. When the model has 6 slits, there were hardly the effect of axial slit wall and the flow transition happened at the same Reynolds number of plain smooth wall model case.

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A flow phenomenon of aquaous polymer solution in couette flow of concentric cylinder with wide circular (넓은 환상간극을 가진 동심원통속의 couette 흐름에서 고분자수용액의 유동현상)

  • 권혁칠;이성노;정진도
    • Journal of the korean Society of Automotive Engineers
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    • v.15 no.3
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    • pp.81-88
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    • 1993
  • This report describes the experimental research on the flow phenomena of the aq uaous polymer solution within the Cuette flow of the concentric, cylinders type with a wide circular gap. We have investigated the phenomena of the fluid flow through torque measuring in the system that the inner cylinder is stationary and the outer one is rotating. Geometrical parameters of the system are the gap ratio of t/R$_{0}$=0.2 and Aspect ratio of l/t=100. The torque increases considerably in about 420-480RPM, So, it is considered a turbulent transition boundary, the higher plymer concentration is, the lower torque value is and the higher transition Reynolds number is. In each of the polymer concentration, the unstable boundary of torque, that is, idiosyncrasies of torque is observed around 220-280RPM. and the boundary is looked upon as a resonant vibration which is caused by the inner cylinder and tortional vibration of torque sensor.r.

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Hall Effect on Couette Flow with Heat Transfer of a Dusty Conducting Fluid Between Parallel Porous Plates Under Exponential Decaying Pressure Gradient

  • Attia Hazem A.
    • Journal of Mechanical Science and Technology
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    • v.20 no.4
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    • pp.569-579
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    • 2006
  • In the present study, the unsteady Couette flow with heat transfer of a dusty viscous incompressible electrically conducting fluid under the influence of an exponential decaying pressure gradient is studied without neglecting the Hall effect. The parallel plates are assumed to be porous and subjected to a uniform suction from above and injection from below while the fluid is acted upon by an external uniform magnetic field is applied perpendicular to the plates. The governing equations are solved numerically using finite differences to yield the velocity and temperature distributions for both the fluid and dust particles.

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.

Hall Effect on Unsteady Couette Flow. with Heat Transfer Under Exponential Decaying Pressure Gradient

  • Attia HazemAIi
    • Journal of Mechanical Science and Technology
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    • v.19 no.11
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    • pp.2053-2060
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    • 2005
  • The unsteady Couette flow of an electrically conducting, V1SCOUS, incompressible fluid bounded by two parallel non-conducting porous plates is studied with heat transfer taking the Hall effect into consideration. An external uniform magnetic field and a uniform suction and injection are applied perpendicular to the plates while the fluid motion is subjected to an exponential decaying pressure gradient. The two plates are kept at different but constant temperatures while the Joule and viscous dissipations are included in the energy equation. The effect of the ion slip and the uniform suction and injection on both the velocity and temperature distributions is examined.

EFFECT OF POROSITY ON THE TRANSIENT MHD GENERALIZED COUETTE FLOW WITH HEAT TRANSFER IN THE PRESENCE OF HEAT SOURCE AND UNIFORM SUCTION AND INJECTION

  • Attia, Hazem Ali;Ewis, Karem Mahmoud;Awad-Allah, Nabil Ahmed
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.16 no.2
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    • pp.125-135
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    • 2012
  • The transient magnetohydrodynamic (MHD) generalized Couette flow with heat transfer through a porous medium of an electrically conducting, viscous, incompressible fluid bounded by two parallel insulating porous plates is studied in the presence of uniform suction and injection and a heat source considering the Hall effect. A uniform and constant pressure gradient is imposed in the axial direction and an externally applied uniform magnetic field as well as a uniform suction and injection are applied in the direction perpendicular to the plates. The two plates are kept at different but constant temperatures while the Joule and viscous dissipations are included in the energy equation. The effect of the Hall current, the porosity of the medium and the uniform suction and injection on both the velocity and temperature distributions is investigated.

Effects of Viscous Dissipation on the Thermal Instability of Plane Couette Flow Heated from Below (밑으로부터 가열되는 평면 Couette 유동에서 점성소산이 열적 불안정성에 미치는 영향)

  • Yoo, Jung Yul;Park, Young Moo
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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    • v.17 no.4
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    • pp.489-498
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    • 1988
  • An analysis has been given for the effect of viscous dissipation on the thermal instability of plane Couette flow between two parallel plates maintained at different constant temperatures. Under the assumption that the principle of the exchange of stabilities holds, stationary disturbance quantities in the form of longitudinal vortices are considered. The magnitudes of disturbance quantities are then represented as fast convergent power series so that the eigenvalue problem for determining the onset conditions of the thermal instability may be reduced to a simplified problem of finding the roots of a $4{\times}4$ determinant. It is shown that as the magnitude of the visucous dissipation increases the flow becomes more susceptible to instabilities, which is in very good agreement with previous results obtained in some related researches.

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