Value Of Free-stream Velocity Research Articles

A significant study on radioactive cross fluid model with melting boundary near stagnation region

The current research endows the mathematical modeling for the stagnation point flow along with melting nonlinear radiative heat transfer for cross fluid. It has many applications such as synthesis of polymer solutions, plastic manufacturing, food processing, preparation of synthesis, adhesives, etc. A radially stretching sheet has started the flow keeping the assumption of rotational symmetry. Transformation approach is adopted to attain the nonlinear ordinary differential equations based on standard conservation laws of mass, linear momentum and also energy. Numerical solutions of the governing problem are computed via the shooting technique. Characteristics of the parameters appearing in modeling like the melting parameter, power–law index, local Weissenberg number, nonlinear radiation parameter, temperature ratio parameter and Prandtl number are comprehensively analyzed through graphical behavior. In addition, comparative analysis is presented for the cases when the value of free stream velocity overtops the stretching velocity and vice versa. Results are authenticated by taking special cases and excellent compatibility is achieved with the existing literature. The detailed analysis anticipates that the boundary layer structures could be strengthened by growing the melting parameter. Elevation in Weissenberg number caused velocity along with temperature profiles to demonstrate for [Formula: see text]. Further, the temperature behaves oppositely analogous to development in nonlinear radiation parameter besides the temperature ratio parameter.

Performance analysis of a savonius vertical axis wind turbine integrated with wind accelerating and guiding rotor house

Though Micro Wind Technology has several advantages but its expansion is very slow due to few significant limitations such as low efficiency of wind turbines and public concerns regarding safety in the turbine vicinity, noise and visual impact. To overcome the limitations of micro wind technology, a Rotor House (RH) for vertical axis wind turbine has been proposed in the literature. It has been claimed that the RH utilizes free stream wind parcel of the area nearly double than the swept area of rotor and amplify velocity magnitude in the rotor zone up to 1.52 times the value of free stream velocity. In the present study contribution of proposed RH in terms of increase in the performance of micro vertical axis wind turbine has been investigated experimentally. In this regard a conventional three bladed savonius rotor model and RH model with optimized design is manufactured and tested under laboratory conditions as well as in open air conditions (field testing). By creating venture effect, the RH accelerates wind flow in the rotor zone and concentrates the flow on the effective location of rotor blade located inside the structure. RH contributes to improve the power coefficient of rotor from 0.125 to 0.218.

English

In this research work the main aim is to reduce the induced drag by using single slotted raked wingtip. Here two wingtip geometries such as a sweptback & tapered wingtip and a slotted raked wingtip are taken for the research work. The tip vortex characteristics of the two different wing geometries at various angles of attacks are shown for different Reynolds numbers such as (1.82 x 105, 3.12 x 105 and 4.16 x 105). These Reynolds numbers are found out by changing the value of free stream velocity only keeping other values constant. The prediction for the numerical result of tangential velocity, lift coefficient and drag coefficient of sweptback and tapered NACA 0015 wing are compared with the experimental results. The numerical results that are obtained by using CFD code show a good agreement with the experimental results. It is observed that, the effect of Reynolds numbers on non-dimensional aerodynamic parameters are seen at higher angles of attack, i.e. above 8° for lift coefficient and above 6o for drag coefficient. It is found that the maximum coefficient of lift (CL max), stalling angle and non-dimensional aerodynamic parameters are increased whereas the drag coefficient is decreased with increase in Reynolds numbers. It is observed that the induced drag is reduced for a single slotted raked wingtip with increase in aerodynamic efficiency as compared to sweptback & tapered wingtip.

Convection cooling of a continuously moving surface in manufacturing processes

An analysis of flow and heat transfer from a heated flat surface continuously moving in a parallel free stream of non-Newtonian fluid has been performed. This kind of problem is of practical interest in materials processing. The surface temperature is assumed to have a power-law variation. Three surface heating conditions of uniform wall temperature (UWT), variable wall temperature (VWT), and uniform surface heat flux (UHF) are considered in this study. Numerical solutions for the momentum and thermal transport between the continuous surface and the flowing non-Newtonian fluid are generated by using a finite-difference method. Velocity and temperature profiles are presented at selected values of free stream velocity using the power-law viscosity index. The friction factor and Nusselt number are illustrated for a wide range of governing parameters. For the same normalized velocity difference, the Nusselt number is increased for a shear thinning fluid but decreased for a shear thickening fluid, as compared to the Newtonian fluid. An increase in the ratio of the free stream velocity U ∞ to the wall velocity U w results in an increase in the heat transfer rate, but a decrease in the friction factor. For the same values of power-law viscosity index and the normalized velocity difference, higher values of friction factor and Nusselt number are obtained from U w> U ∞ than from U w< U ∞. Furthermore, the heat transfer rate increases with increasing the values of wall temperature exponent and the generalized Prandtl number but decreases with increasing normalized velocity difference.

Forced convection over a continuous sheet with suction or injection moving in a flowing fluid

The analysis of forced convection flow and heat transfer about a flat sheet with suction or injection continuously moving in a quiescent or flowing fluid has been carried out. This kind of problem finds applications in a variety of manufacturing processes such as hot rolling, extrusion of plastic sheets, continuous casting, and cooling of a metallic plate in a cooling bath. The governing differential equations are reduced to nonlinear ordinary differential equations by similarity transformations. These equations are solved numerically based on a finite difference algorithm. Representative velocity and temperature profiles within the boundary layer are presented at selected values of free stream velocity and injection parameter. The friction factor and Nusselt number are illustrated for a wide range of governing parameters. For the same injection parameter, Prandtl number, and normalized velocity difference |Uw−U∞|, higher values of the Nusselt number and friction factor result fromUw>U∞ than fromUw<U∞. Also, an increase in the velocity ratioU∞/Uw results in an increase in the heat transfer rate, but a decrease in the friction factor. Furthermore, the heat transfer is enhanced due to increasing the values of the free stream velocity, the injection parameter, and Prandtl number; while it is reduced due to increasing the velocity difference.