Browsing by Author "Muhammad Imran Asjad"

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    Analytic solutions of oldyrod-b fluid with fractional derivatives in a circular duct that applies a constant couple
    (Alexendria Engineering Journal, Elsevier, 2016) Muhammad Bilal Riaz; Muhammad Imran Asjad
    The aim of this article was to analyze the rotational flow of an Oldroyd-B fluid with fractional derivatives, induced by an infinite circular cylinder that applies a constant couple to the fluid. Such kind of problem in the settings of fractional derivatives has not been found in the literature. The solutions are based on an important remark regarding the governing equation for the nontrivial shear stress. The solutions that have been obtained satisfy all imposed initial and boundary conditions and can easily be reduced to the similar solutions corresponding to ordinary Oldroyd-B, fractional/ordinary Maxwell, fractional/ordinary second-grade, and Newtonian fluids performing the same motion. The obtained results are expressed in terms of Newtonian and non-Newtonian contributions. Finally, the influence of fractional parameters on the velocity, shear stress and a comparison between generalized and ordinary fluids is graphically underlined.
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    Effects of slip on free convection flow of casson fluid over an oscillating vertical plate.
    (Boundary Value Problem, Springer, 2016) Muhammad Imran Asjad; Shakila Sarwar
    The slip effect on free convection of a Casson fluid past an infinite oscillating vertical plate with constant wall temperature is investigated. It is used to characterize the non-Newtonian fluid behavior. By introducing appropriate non-dimensional variables, the resulting equations are solved analytically by using the Laplace transform technique. The corresponding solutions for a Casson fluid without slip at the boundary for λ → 0, a Newtonian fluid with slip for γ → ∞, and a Newtonian fluid in the absence of slip for λ → 0 and γ → ∞ are obtained as limiting cases. The effect of the Casson parameter is seen to suppress the velocity field. Also, the influence of the slip parameter causes a decrease in the velocity field. Numerical results for velocity, temperature, and Nusselt number are shown in various graphs and discussed for the embedded flow parameters.