جستجوی مقالات مرتبط با کلیدواژه « stretching » در نشریات گروه « مکانیک »

A detailed analysis, is presented in this paper, for the steady gyrostatic nanofluid flow past a permeable stretching/shrinking sheet with slip condition using the nanofluid model proposed by Buongiorno. The microorganisms are imposed into the nanofluid to stabilize the nanoparticles to suspend due to a phenomenon called bioconvection. Considering appropriate similarity transformations, the five partial differential equations of mass conservation, momentum, thermal energy and microorganisms are reduced to a set of four ordinary (similar) differential equations with coupled linear boundary conditions. These equations   were both analytical and numerical solved using Runge-Kutta-Fehlberg technique. The influences of important physical parameters, such as, Prandtl number Pr, the Schmidt number Sc, the bioconvection Péclet number Pe, the Brownian motion parameter Nb, the thermophoresis parameter Nt and the stretching/shrinking parameter λ on the skin friction coefficient Cf and the local Nusselt number Nux, as well as on the velocity, temperature and gyration profiles, are interpreted through graphs and tables. Further, multiple (dual, upper and lower branch solutions) are found for the governing similarity equations and the upper branch solution expanded with higher values of the suction parameter. It can be confirmed that the lower branch solution is unstable. It is found that the bioconvection parameters have strong influence towards the reduced skin friction coefficient, reduced heat transfer, velocity and density of motile microorganism’s transport rates.

In the present investigation, the magnetohydrodynamic Falkner-Skan flow of tangent hyperbolic nanofluids over a stretching/shrinking wedge with variable suction, internal heat generation/absorption and chemical reaction with activation energy have been scrutinized. Nanofluid model is composed of “Brownian motion’’ and “Thermophoresis’’. Transformed non-dimensional coupled non-linear equations are solved by adopting the fourth-order R-K method along with the shooting technique. A comprehensive analysis of nanofluid velocity, the relative temperature, and its concentration profiles has been addressed. The major outcomes of the current study include that augmentation in the Weissenberg parameter, Hartmann number along with suction impede fluid flow and the shrinkage of the related boundary layer while internal heating develops an ascending thermal boundary layer for static and moving (stretching/shrinking) wedge. An increment in reaction rate undermines the nanoparticle concentration while that of activation energy exhibits a reverse trend.

In this article, bending-stretching analysis of thick rectangular plate made of functionally graded material has been investigated based on higher order shear and normal deformable theory which was introduced by Batra and Vilodi. In this theory, both shear and normal deformation effects in the thickness direction are considered. Also, the deflection of plate is not considered as a constant in the thickness direction. A power law function is used to describe the mechanical properties of the functionally graded plate. The numerical results have been presented for first to fifth order shear and normal deformable theory in tables and diagrams. The effects of functionally graded material properties on deflection and stresses of plate have been studied for various thickness and dimensions of the plate. It is shown that this theory gives accurate results not only for thin and moderately thick plates, but also for functionally graded thick plates.

In this paper, the steady laminar boundary layer flow and heat transfer over a permeable exponentially stretching/shrinking sheet with generalized slip velocity is studied. The flow and heat transfer induced by stretching/shrinking sheets are important in the study of extrusion processes and is a subject of considerable interest in the contemporary literature. Appropriate similarity variables are used to transform the governing nonlinear partial differential equations to a system of nonlinear ordinary (similarity) differential equations. The transformed equations are then solved numerically using the bvp4c function in MATLAB. Dual (upper and lower branch) solutions are found for a certain range of the suction and stretching/shrinking parameters. Stability analysis is performed to determine which solutions are stable and physically realizable and which are not stable. The effects of suction parameter, stretching/shrinking parameter, velocity slip parameter, critical shear rate and Prandtl number on the skin friction and heat transfer coefficients as well as the velocity and temperature profiles are presented and discussed in detail. It is found that the introduction of the generalized slip boundary condition resulted in the reduction of the local skin friction coefficient and local Nusselt number. Finally, it is concluded from the stability analysis that the first (upper branch) solution is stable while the second (lower branch) solution is not stable.

In this study we analyzed the momentum and heat transfer behavior of CuO-water and A 2O3-waternanofluids embedded with micrometer sized conducting dust particles towards a porous stretching/shrinking cylinder at different temperatures in presence of suction/injection, uniform magnetic field, shape of nano particles, volume fraction of micro and nano particles. The governing boundary layer equations are transformed to nonlinear ordinary differential equations by using similarity transformation. Numerical solutions of these equations can be obtained by using Runge-Kutta Felhberg technique. The influence of non-dimensional governing parameters on the flow field and heat transfer characteristics are discussed and presented through graphs and tables. Results indicates that spherical shaped nano particles showed better thermal enhancement compared with cylindrical shaped nano particles, increase in volume fraction of nano particles helps to enhance the uniform thermal conductivity. But it does not happen by increase in volume fraction of dust particles. Enhancement in fluid particle interaction reduces the friction factor and improves the heat transfer rate.

A study has been carried out on MHD boundary layer forced convection flow along a shrinking surface with variable heat flux in the presence of heat source. The flow is generated due to linear shrinking of the sheet and is influenced by uniform transverse magnetic field. The basic boundary layer momentum and heat transfer equations, which are nonlinear partial differential equations, are converted into nonlinear ordinary differential equations by means of similarity transformation. Numerical solution of the resulting boundary value problem is obtained using Nachtsheim Swigert shooting iteration scheme for the satisfaction of asymptotic boundary conditions along with the Fourth Order Runge Kutta method. The effects of suction parameter, magnetic parameter, Prandtl number, heat source parameter, stretching/shrinking parameter and heat flux parameter on velocity and temperature are shown in several plots. The results are in good agreement with the earlier published works under some limiting cases. Skin friction coefficient and wall temperature are also explored for typical values of the parameter involved in the study.