Browsing by Author "Hayat, T"

Now showing 1 - 4 of 4
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    Group-Theoretic Approach to Boundary Layer Equations of an Oldroy-B Fluid
    Pakdemirli, M; Hayat, T; Aksoy, Y
    Boundary layer equations are derived for the first time for an Oldroy-B fluid. The symmetry analysis of the equations is performed using Lie Group theory and the partial differential system is transferred to an ordinary differential system via symmetries. Resulting equations are numerically solved for the case of the stretching sheet problem. Effects of non-Newtonian parameters on the solutions are discussed.
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    Boundary Layer Theory and Symmetry Analysis of a Williamson Fluid
    Aksoy, Y; Hayat, T; Pakdemirli, M
    Boundary layer equations are derived for the first time for a Williamson fluid. Using Lie group theory. a symmetry analysis of the equations is performed. The partial differential system is transferred to an ordinary differential system via symmetries, and the resulting equations are numerically solved. Finally. the effects of the non-Newtonian parameters on the solutions are discussed.
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    Boundary Layer Equations and Lie Group Analysis of a Sisko Fluid
    Sari, G; Pakdemirli, M; Hayat, T; Aksoy, Y
    Boundary layer equations are derived for the Sisko fluid. Using Lie group theory, a symmetry analysis of the equations is performed. A partial differential system is transferred to an ordinary differential system via symmetries. Resulting equations are numerically solved. Effects of non-Newtonian parameters on the solutions are discussed.
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    Perturbation analysis of a modified second grade fluid over a porous plate
    Pakdemirli, M; Hayat, T; Yürüsoy, M; Abbasbandy, S; Asghar, S
    A modified second grade non-Newtonian fluid model is considered. The model is a combination of power-law and second grade fluids in which the fluid may exhibit normal stresses, shear thinning or shear thickening behaviors. The flow of this fluid is considered over a porous plate. Equations of motion in dimensionless form are derived. When the power-law effects are small compared to second grade effects, a regular perturbation problem arises which is solved. The validity criterion for the solution is derived. When second grade effects are small compared to power-law effects, or when both effects are small, the problem becomes a boundary layer problem for which the solutions are also obtained. Perturbation solutions are contrasted with the numerical solutions. For the regular perturbation problem of small power-law effects, an excellent match is observed between the solutions if the validity criterion is met. For the boundary layer solution of vanishing second grade effects however, the agreement with the numerical data is not good. When both effects are considered small, the boundary layer solution leads to the same solution given in the case of a regular perturbation problem. (C) 2010 Elsevier Ltd. All rights reserved.