The Experts below are selected from a list of 8823 Experts worldwide ranked by ideXlab platform
Arun S Mujumdar - One of the best experts on this subject based on the ideXlab platform.
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enhanced heat transfer in free convection dominated melting in a Rectangular Cavity with an isothermal vertical wall
Applied Thermal Engineering, 1999Co-Authors: Zhenxiang Gong, Sakamon Devahastin, Arun S MujumdarAbstract:Abstract Free convection-dominated melting of a phase change material in a Rectangular Cavity with an isothermally heated vertical wall is simulated using the streamline upwind/Petrov–Galerkin finite element technique in combination with a fixed-grid primitive variable method. The enthalpy–porosity model is employed to account for the physics of the evolution of the flow at the solid/liquid interface. A penalty formulation is used to treat the incompressibility constraint in the momentum equations. Inverting of the container at an appropriate stage during the melting process is proposed as a simple but effective technique for enhancement of free convection-controlled heat transfer in the phase change material. The technique results in more than 50% increase of the energy charge rate during the melting process for some specific cases.
V V Meleshko - One of the best experts on this subject based on the ideXlab platform.
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steady stokes flow in a Rectangular Cavity
Proceedings of The Royal Society A: Mathematical Physical and Engineering Sciences, 1996Co-Authors: V V MeleshkoAbstract:This paper addresses a general analytical method for investigating the two-dimensional creeping flow field set up in a Rectangular Cavity by velocities applied along its top and bottom walls in any arbitrary manner. The main goal is to prove the advantages of that approach when studying a local stream function behaviour near the corner points. The values of amplitudes of the so-called corner eddies were established based on the solution of the finite system of linear algebraic equations. The method is illustrated by several numerical examples. The rapidity of convergence and the accuracy of results are investigated. The streamline patterns for some typical distribution of velocities are shown graphically.
Steven J Beresh - One of the best experts on this subject based on the ideXlab platform.
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compressibility effects in the shear layer over a Rectangular Cavity
Journal of Fluid Mechanics, 2016Co-Authors: Steven J Beresh, Justin L Wagner, Katya M CasperAbstract:The influence of compressibility on the shear layer over a Rectangular Cavity of variable width has been studied in a free stream Mach number range of 0.6–2.5 using particle image velocimetry data in the streamwise centre plane. As the Mach number increases, the vertical component of the turbulence intensity diminishes modestly in the widest Cavity, but the two narrower cavities show a more substantial drop in all three components as well as the turbulent shear stress. This contrasts with canonical free shear layers, which show significant reductions in only the vertical component and the turbulent shear stress due to compressibility. The vorticity thickness of the Cavity shear layer grows rapidly as it initially develops, then transitions to a slower growth rate once its instability saturates. When normalized by their estimated incompressible values, the growth rates prior to saturation display the classic compressibility effect of suppression as the convective Mach number rises, in excellent agreement with comparable free shear layer data. The specific trend of the reduction in growth rate due to compressibility is modified by the Cavity width.
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width effects in transonic flow over a Rectangular Cavity
AIAA Journal, 2015Co-Authors: Steven J Beresh, Justin L Wagner, John F Henfling, Russell Spillers, Brian Owen Matthew PruettAbstract:A previous experiment by the present authors studied the flow over a finite-width Rectangular Cavity at freestream Mach numbers 1.5–2.5. In addition, this investigation considered the influence of three-dimensional geometry that is not replicated by simplified cavities that extend across the entire wind-tunnel test section. The latter configurations have the attraction of easy optical access into the depths of the Cavity, but they do not reproduce effects upon the turbulent structures and acoustic modes due to the length-to-width ratio, which is becoming recognized as an important parameter describing the nature of the flow within narrower cavities.
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supersonic flow over a finite width Rectangular Cavity
AIAA Journal, 2015Co-Authors: Steven J Beresh, Justin L Wagner, John F Henfling, Brian Owen Matthew Pruett, Russell SpillersAbstract:Two-component and stereoscopic particle image velocimetry measurements have been acquired in the streamwise plane for supersonic flow over a Rectangular Cavity of variable width, peering over the sidewall lip to view the depths of the Cavity. The data reveal the turbulent shear layer over the Cavity and the recirculation region within it. The mean position of the recirculation region was found to be a function of the length-to-width ratio of the Cavity, as was the turbulence intensity within both the shear layer and the recirculation region. Compressibility effects were observed in which turbulence levels dropped, and the shear layer thickness decreased as the Mach number was raised from 1.5 to 2.0 and 2.5. Supplemental measurements in the crossplane and the planform view suggest that zones of high turbulence were affixed to each sidewall centered on the Cavity lip, with a strip of turbulence stretched out across the Cavity shear layer for which the intensity was a function of the length-to-width ratio. T...
A Levy - One of the best experts on this subject based on the ideXlab platform.
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numerical and experimental study of the traveling magnetic field effect on the horizontal solidification in a Rectangular Cavity part 1 liquid metal flow under the tmf impact
International Journal of Heat and Fluid Flow, 2018Co-Authors: M H Avnaim, B Mikhailovich, A Azulay, A LevyAbstract:Abstract Traveling magnetic field is one of effective tools for controlling phase change processes in metals. A better understanding of electromagnetic impact in such applications can help to improve and simplify technological processes. In this paper, numerical and experimental study of the electromagnetic force generated by traveling magnetic field and its ability to control liquid gallium flow and, consequently, affect the characteristics of solidification and melting processes are evaluated. Three-dimensional numerical model for calculating the magnetic field distribution and electromagnetic force acting on liquid gallium in a laboratory-size Rectangular Cavity was analyzed. Specific values of the TMF impact were chosen for the cases of interest in order to use such impact in our further work with horizontal gallium solidification process. The traveling magnetic field inductor was designed and built for making appropriate measurements and validating calculations. The analysis was focused on the electromagnetic force and the obtained velocity field. The experimental setup included an ultrasonic Doppler velocimeter for noninvasive measurements of the velocities of liquid metal flow. The comparison of computations with the experiments has shown a good agreement.
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Numerical and experimental study of the traveling magnetic field effect on the horizontal solidification in a Rectangular Cavity part 2: Acting forces ratio and solidification parameters
International Journal of Heat and Fluid Flow, 2018Co-Authors: M H Avnaim, B Mikhailovich, A Azulay, A LevyAbstract:Abstract In recent decades, many phase change processes in metals have been optimized using traveling magnetic fields due to a better understanding of their electromagnetic impact in such applications. In this paper, numerical and experimental study of the effect of traveling magnetic field on the solidification process was evaluated. A three-dimensional numerical model based on the multi-domain method was used to analyze the process of gallium horizontal solidification under the electromagnetic impact in a laboratory-size Rectangular Cavity. A linear inductor creating traveling magnetic field was designed and built for appropriate measurements and validation the calculations. The analysis was focused on the influence of the ratio between the applied electromagnetic forces and natural convective forces on the solidification front location and shape and on the velocity field. Since the overall electromagnetic force impact on the melt reduced during the solidification, when the melt area was converting into a solid, a new approach to control the solidification parameters was analyzed. In this approach, the value of electromagnetic force acting on the remaining melt during the process was maintained. The main result is the development and improvement of an effective tool for the analysis of direct solidification parameters. The experimental setup included an ultrasonic Doppler velocimeter (UDV) for noninvasive measurements of the velocities in the liquid part of the metal and the liquid-solid interface position, its profile and displacement. All important characteristics of the process were measured, and the results of computations agreed well enough with experimentally obtained data.
Taner Derbentli - One of the best experts on this subject based on the ideXlab platform.
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three dimensional natural convection and radiation in a Rectangular Cavity with one active vertical wall
Experimental Thermal and Fluid Science, 2017Co-Authors: Hakan Karatas, Taner DerbentliAbstract:Abstract Three-dimensional study of natural convection in a closed Rectangular Cavity has been carried out. The Rectangular Cavity is 340 mm high, 163 mm long and 210 mm deep. The aspect ratio of the Rectangular Cavity is 2.09. The Cavity is filled with air. The Cavity has one active vertical wall. The opposing vertical wall is inactive and insulated from the back. The other four walls are adiabatic. Combined radiation and natural convection in the Cavity is studied experimentally. Thermocouples are used to measure the temperature. The temperature distribution between the vertical walls of the Cavity is obtained at 35 positions in the length direction, five positions in the height direction and five positions in the depth direction. In the central region of the Cavity, the temperature gradient is low and the temperature profile shows a linear variation. In the near wall regions, the temperature gradient is high and the temperature sharply increases. The isotherms in the Cavity are obtained for five Cavity depths. The variation of the Nusselt number with the Cavity height and depth is presented. The average Nusselt number is obtained by taking the weighted average of the results. The Rayleigh number is 3.78 × 10 6 .
