Current Issue : October - December Volume : 2014 Issue Number : 4 Articles : 5 Articles
A new analytical algorithm based on modified homotopy perturbation transformmethod is employed for solving the transient flow\nof third grade fluid in a porous channel generated by an oscillating upper wall. This method incorporates the He�s polynomial into\nthe HPM, combined with Laplace transform. Comparison with HPM and OHAM analytical solutions reveals that the proposed\nalgorithm is highly accurate. This proves the validity and great potential of the proposed algorithm as a new kind of powerful\nanalytical tool for transient nonlinear problems. Graphs representing the solutions are discussed, and appropriate conclusions are\ndrawn....
A direct numerical simulation (DNS) was carried out to study twin swirling jets which are issued from two parallel nozzles at a\nReynolds number of Re = 5000 and three swirl levels of S = 0.68, 1.08, and 1.42, respectively.The basic structures of vortex-vortex\ninteraction and temporal evolution are illustrated.Thecharacteristics of axial variation of turbulent fluctuation velocities, in both the\nnear and far field, in comparison to a single swirling jet, are shown to explore the effects of vortex-vortex interaction on turbulence\nmodifications.Moreover, the second order turbulent fluctuations are also shown, bywhich themodification of turbulence associated\nwith the coherent or correlated turbulent fluctuation and turbulent kinetic energy transport characteristics are clearly indicated. It is\nfound that the twin swirling flow has a fairly strong localized vortex-vortex interaction between a pair of inversely rotated vortices.\nThe location and strength of interaction depend on swirl level greatly.Themodification of vortex takes place by transforming largescale\nvortices into complex small ones, whereas the modulation of turbulent kinetic energy is continuously augmented by strong\nvortex modification....
The problem of the flexural vibrations of a rectangular plate having arbitrary supports at both ends is investigated. The solution\ntechnique which is suitable for all variants of classical boundary conditions involves using the generalized two-dimensional integral\ntransform to reduce the fourth order partial differential equation governing the vibration of the plate to a second order ordinary\ndifferential equation which is then treated with the modified asymptotic method of Struble.The closed formsolutions are obtained\nand numerical analyses in plotted curves are presented. It is also deduced that for the same natural frequency, the critical speed\nfor the system traversed by uniformly distributed moving forces at constant speed is greater than that of the uniformly distributed\nmoving mass problem for both clamped-clamped and simple-clamped end conditions. Hence resonance is reached earlier in the\nuniformly distributed moving mass system. Furthermore, for both structural parameters considered, the response amplitude of the\nmoving distributed mass system is higher than that of the moving distributed force system.Thus, it is established that the moving\ndistributed force solution is not an upper bound for an accurate solution of the moving distributed mass problem....
The purpose of this study is to investigate the natural convection laminar flow along an isothermal vertical flat plate immersed in\na fluid with viscosity which is the exponential function of fluid temperature in presence of internal heat generation.The governing\nboundary layer equations are transformed into a nondimensional form and the resulting nonlinear system of partial differential\nequations is reduced to a convenient form which are solved numerically using an efficient marching order implicit finite difference\nmethod with double sweep technique. Numerical results are presented in terms of the velocity and temperature distribution of the\nfluid as well as the heat transfer characteristics, namely, the wall shear stress and the local and average rate of heat transfer in terms\nof the local skin-friction coefficient, the local and averageNusselt number for a wide range of the viscosity-variation parameter, heat\ngeneration parameter, and the Rayleigh number. Increasing viscosity variation parameter and Rayleigh number lead to increasing\nthe local and average Nusselt number and decreasing thewall shear stress.Wall shear stress and the rate of heat transfer decreased\ndue to the increase of heat generation....
This paper proposes a computational approach to debris flow model. In recent years, the theoretical activity on the classical\nHerschel-Bulkley model (1926) has been very intense, but it was in the early 80s that the opportunity to explore the computational\nmodel has enabled considerable progress in identifying the subclasses of applicability of different sets of boundary conditions and\ntheir approximations. Here we investigate analytically the problem of the simulation of uniform motion for heterogeneous debris\nflowlaterally confined taking into accountmainly the geological data and methodological suggestions derived fromsimulation with\ncellular automata and grid systems, in order to propose a computational scheme able to operate a compromise between ââ?¬Å?globalââ?¬Â\npredictive capacities and computing effort....
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