The Experts below are selected from a list of 9765 Experts worldwide ranked by ideXlab platform
Anuar Ishak - One of the best experts on this subject based on the ideXlab platform.
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Biorthogonal stretching and shearing of an Impermeable Surface in a uniformly rotating fluid system
Meccanica, 2017Co-Authors: Patrick D. Weidman, Syahira Mansur, Anuar IshakAbstract:The flow induced by an Impermeable flat Surface executing orthogonal stretching and orthogonal shearing in a rotating fluid system is investigated. Both the stretching and shearing are linear in the coordinates. An exact similarity reduction of the Navier–Stokes equations gives rise to a pair of nonlinearly-coupled ordinary differential equations governed by three parameters. In this study we set one parameter and analyze the problem which leads to flow for an Impermeable Surface with shearing and stretching due to velocity u along the x -axis of equal strength a while the shearing and stretching due to velocity v along the y -axis of equal strength b . These solutions depend on two parameters—a Coriolis (rotation) parameter $$\sigma = \Omega /a$$ σ = Ω / a and a stretching/shearing ratio $$\lambda =b/a$$ λ = b / a . A symmetry in solutions is found for $$\lambda = 1$$ λ = 1 . The exact solution for $$\sigma = 0$$ σ = 0 and the asymptotic behavior of solutions for $$|\sigma | \rightarrow \infty$$ | σ | → ∞ are determined and compared with numerical results. Oscillatory solutions are found whose strength increases with increasing values of $$|\sigma |$$ | σ | . It is shown that these solutions tend to the well-known Ekman solution as $$|\sigma | \rightarrow \infty$$ | σ | → ∞ .
Ioan Pop - One of the best experts on this subject based on the ideXlab platform.
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Effect of variable viscosity on mixed convection boundary layer flow over a vertical Surface embedded in a porous medium
International Communications in Heat and Mass Transfer, 2007Co-Authors: Kin Eng Chin, Roslinda Mohd. Nazar, Norihan Md. Arifin, Ioan PopAbstract:The steady mixed convection boundary layer flow over a vertical Impermeable Surface embedded in a porous medium when the viscosity of the fluid varies inversely as a linear function of the temperature is studied. Both cases of assisting and opposing flows are considered. The transformed boundary layer equations are solved numerically by a finite difference method. Numerical results for the flow and heat transfer characteristics are obtained for various values of the mixed convection parameter e and the variable viscosity parameter θe. It has been found that in the opposing flow case, dual solutions exist and boundary separation occurs.
Jacques Magnaudet - One of the best experts on this subject based on the ideXlab platform.
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high reynolds number turbulence in a shear free boundary layer revisiting the hunt graham theory
Journal of Fluid Mechanics, 2003Co-Authors: Jacques MagnaudetAbstract:The capability of rapid distortion theory to predict the long-time evolution of shearless turbulence close to an Impermeable Surface has been seriously questioned in recent years. However, experiments and large-eddy simulations performed at high Reynolds number show that second-order turbulence statistics follow closely the predictions of the theory elaborated by Hunt & Graham. To clarify this issue, a theoretical analysis is carried out in order to determine the relative magnitude of the vortical corrections which were not taken into account in the original theory. By evaluating the various terms of the enstrophy balance in the near-Surface region, it is shown that this relative magnitude is a decreasing function of the turbulent Reynolds number, an argument reconciling most existing results. Hence the Hunt & Graham theory appears to be a leading-order approximation capable of describing short- and long-time evolutions of shear-free boundary layers in the limit of large Reynolds number. The expression for the pressure fluctuation corresponding to this approximation is then derived and approximate Reynolds stress budgets are obtained
Patrick D. Weidman - One of the best experts on this subject based on the ideXlab platform.
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Biorthogonal stretching and shearing of an Impermeable Surface in a uniformly rotating fluid system
Meccanica, 2017Co-Authors: Patrick D. Weidman, Syahira Mansur, Anuar IshakAbstract:The flow induced by an Impermeable flat Surface executing orthogonal stretching and orthogonal shearing in a rotating fluid system is investigated. Both the stretching and shearing are linear in the coordinates. An exact similarity reduction of the Navier–Stokes equations gives rise to a pair of nonlinearly-coupled ordinary differential equations governed by three parameters. In this study we set one parameter and analyze the problem which leads to flow for an Impermeable Surface with shearing and stretching due to velocity u along the x -axis of equal strength a while the shearing and stretching due to velocity v along the y -axis of equal strength b . These solutions depend on two parameters—a Coriolis (rotation) parameter $$\sigma = \Omega /a$$ σ = Ω / a and a stretching/shearing ratio $$\lambda =b/a$$ λ = b / a . A symmetry in solutions is found for $$\lambda = 1$$ λ = 1 . The exact solution for $$\sigma = 0$$ σ = 0 and the asymptotic behavior of solutions for $$|\sigma | \rightarrow \infty$$ | σ | → ∞ are determined and compared with numerical results. Oscillatory solutions are found whose strength increases with increasing values of $$|\sigma |$$ | σ | . It is shown that these solutions tend to the well-known Ekman solution as $$|\sigma | \rightarrow \infty$$ | σ | → ∞ .
Kin Eng Chin - One of the best experts on this subject based on the ideXlab platform.
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Effect of variable viscosity on mixed convection boundary layer flow over a vertical Surface embedded in a porous medium
International Communications in Heat and Mass Transfer, 2007Co-Authors: Kin Eng Chin, Roslinda Mohd. Nazar, Norihan Md. Arifin, Ioan PopAbstract:The steady mixed convection boundary layer flow over a vertical Impermeable Surface embedded in a porous medium when the viscosity of the fluid varies inversely as a linear function of the temperature is studied. Both cases of assisting and opposing flows are considered. The transformed boundary layer equations are solved numerically by a finite difference method. Numerical results for the flow and heat transfer characteristics are obtained for various values of the mixed convection parameter e and the variable viscosity parameter θe. It has been found that in the opposing flow case, dual solutions exist and boundary separation occurs.