Unsteady Mixed Convection Flow along Symmetric Wedge with Variable Surface Temperature Embedded in a Porous Medium Saturated with a Nanofluid

Laminar two-dimensional unsteady mixed-convection boundary-layer flow of a viscous incompressible fluid past asymmetric wedge with variable surface temperature embedded in a porous medium saturated with a nanofluid has been studied. The employed mathematical model for the nanofluid takes into account the effects of Brownian motion and thermophoresis. The velocity in the potential flow is assumed to vary arbitrary with time. The non-Darcy effects including convective, boundary and inertial effects will be included in the analysis. The unsteadiness is due to the time-dependent free stream velocity. The governing boundary layer equations along with the boundary conditions are converted into dimensionless form by a non-similar transformation, and then resulting system of coupled non-linear partial differential equations are solved by perturbation solutions for small dimensionless time until the second order. Numerical solutions of the governing equations are obtained employing the implicit finite-difference scheme in combination with the quasi-linearization technique. To validating the method used, we compared our results with previous results in earlier papers on special cases of the problem and are found to be in agreement. Effects of various parameters on velocity, temperature and nanoparticle volume fraction profiles are graphically presented.

FLUID FLOW SEPARATION CHARACTER ON NOVEL HYBRID JOURNAL BEARING

The influence of the structure and running parameters of a novel spiral oil wedge hybrid journal bearing on the fluid flow trace is investigated. The governing equation of the flow trace of lubricant is set up, and the simulation is carried out by using finite difference method. The results show that the lubricant flow status and end leakage quantity are greatly influenced by spiral angle,and that the rotating speed has little influence on the flow status. With advisable geometry design, the separation of lubricant between different oil wedges can be obtained, which can decrease the temperature rise effectively.

RESEARCH ON DISTRIBUTION FUNCTION AND ORIENTATION TENSORS OF FIBER SUSPENSIONS IN WEDGE-SHAPED FLOW FIELD

The distribution function and orientation tensor of fiber suspensions in wedge shaped flow field were computed . The results indicate that with time increasing, the fiber orient themselves to flow direction gradually. At the locations with same pole radii, the angle between fiber orientation and centerline, which occurs with the most probability, decreases with the pole angle increasing . At the locations with same pole angle, the angle between fiber orientation and centerline increases with the pole radii decreasing. The second order tensors get steady more quickly at the points where the velocity g radients are larger. At the locations with same pole angle, the steady values of orientation tensors are identical. At the locations with same pole radii is, streamline becomes flatter as the pole angle decreases.

The Himalayan Collisional Orogeny:A Metamorphic Perspective

This paper introduces how crustal thickening controls the growth of the Himalaya by summarizing the P-T-t evolution of the Himalayan metamorphic core.The Himalayan orogeny was divided into three stages.Stage 60–40 Ma:The Himalayan crust thickened to~40 km through Barrovian-type metamorphism(15–25°C/km),and the Himalaya rose from<0 to~1000 m.Stage 40–16 Ma:The crust gradually thickened to 60–70 km,resulting in abundant high-grade metamorphism and anatexis(peak-P,15–25°C/km;peak-T,>30°C/km).The three sub-sheets in the Himalayan metamorphic core extruded southward sequentially through imbricate thrusts of the Eo-Himalayan thrust,High Himalayan thrust,and Main Central thrust,and the Himalaya rose to≥5,000 m.Stage 16–0 Ma:the mountain roots underwent localized delamination,causing asthenospheric upwelling and overprinting of the lower crust by ultra-high-temperature metamorphism(30–50°C/km),and the Himalaya reached the present elevation of~6,000 m.Underplating and imbricate thrusting dominated the Himalaya’growth and topographic rise,conforming to the critical taper wedge model.Localized delamination of mountain roots facilitated further topographic rise.Future Himalayan metamorphic studies should focus on extreme metamorphism and major collisional events,contact metamorphism and rare metal mineralization,metamorphic decarbonation and the carbon cycle in collisional belts.