Flow Patterns in Time Dependent Double Diffusive Natural Convection in a Stably Fluid Under Partial Heating Boundary Condition for a Circular Cavity

2002 ◽  
Vol 2002 (0) ◽  
pp. 215-216
Author(s):  
Jamshid POURESFANDIARY CHAM ◽  
Shigeru HINATA ◽  
Nobuhiro HIMENO ◽  
Masayuki SAKURAI ◽  
Katsuyoshi KAMAKURA
Keyword(s):  
Boundary Condition ◽  
Natural Convection ◽  
Flow Patterns ◽  
Time Dependent ◽  
Circular Cavity ◽  
Partial Heating ◽  
Double Diffusive

An Experimental Study of Circulation Patterns in Natural Convection Using PIV

2003 ◽  
Author(s):  
K. M. Akyuzlu ◽  
S. Nemani ◽  
K. Chakravarthy
Keyword(s):  
Boundary Condition ◽  
Natural Convection ◽  
Velocity Field ◽  
Flow Patterns ◽  
Constant Heat Flux ◽  
Working Fluid ◽  
Constant Wall Temperature ◽  
Flux Boundary Condition ◽  
Circulation Patterns ◽  
Contour Plots

The objective of this study is to investigate, experimentally, using Particle Image Velocimeter (PIV), the effect of different heat transfer boundary conditions on natural convection (specifically on flow patterns) inside a storage tank (a rectangular enclosure in this case with an aspect ratio of 0.5.) Purified water is used as the working fluid and it is seeded with 10 micron hollow glass sphere particles. The results of the first set of experiments are used to verify the flow patterns expected for the constant wall temperature boundary condition, the benchmark case. Similar experiments are conducted for the constant heat flux boundary condition. The Rayleigh number for all the cases studied lie between 106 and 107. The time averaged velocity field is determined using standard cross correlation techniques. Streamlines, and velocity contour plots are generated using this velocity field. Finally, the results of both cases are compared to identify the differences in circulation patterns and thermal stratification in the fluid.

UNSTEADY DOUBLE-DIFFUSIVE NATURAL CONVECTION AND THERMAL RADIATION WITHIN A VERTICAL POROUS ENCLOSURE

2013 ◽  
Vol 16 (2) ◽  
pp. 167-182 ◽  
Author(s):  
Abdesslem Jbara ◽  
Hosni Souheil Harzallah ◽  
Khalifa Slimi ◽  
Abdallah Mhimid
Keyword(s):  
Natural Convection ◽  
Thermal Radiation ◽  
Double Diffusive ◽  
Porous Enclosure

Incompressible smoothed particle hydrodynamics for MHD double-diffusive natural convection of a nanofluid in a cavity containing an oscillating pipe

2019 ◽  
Vol 30 (2) ◽  
pp. 882-917 ◽  
Author(s):  
Abdelraheem M. Aly
Keyword(s):  
Natural Convection ◽  
Smoothed Particle Hydrodynamics ◽  
Cavity Wall ◽  
Lagrangian Description ◽  
Content Type ◽  
Wide Range ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Incompressible Smoothed Particle Hydrodynamics ◽  
Double Diffusive

Purpose This paper aims to adopt incompressible smoothed particle hydrodynamics (ISPH) method to simulate MHD double-diffusive natural convection in a cavity containing an oscillating pipe and filled with nanofluid. Design/methodology/approach The Lagrangian description of the governing partial differential equations are solved numerically using improved ISPH method. The inner oscillating pipe is divided into two different pipes as an open and a closed pipe. The sidewalls of the cavity are cooled with a lower concentration C_c and the horizontal walls are adiabatic. The inner pipe is heated with higher concentration C_h. The analysis has been conducted for the two different cases of inner oscillating pipes under the effects of wide range of governing parameters. Findings It is found that a suitable oscillating pipe makes a well convective transport inside a cavity. Presence of the oscillating pipe has effects on the heat and mass transfer and fluid intensity inside a cavity. Hartman parameter suppresses the velocity and weakens the maximum values of the stream function. An increase on Hartman, Lewis and solid volume fraction parameters leads to an increase on average Nusselt number on an oscillating pipe and left cavity wall. Average Sherwood number on an oscillating pipe and left cavity wall decreases as Hartman parameter increases. Originality/value The main objective of this work is to study the MHD double-diffusive natural convection of a nanofluid in a square cavity containing an oscillating pipe using improved ISPH method.

Natural Convection in a Horizontal Layer of Water Cooled From Above to Near Freezing

1975 ◽  
Vol 97 (1) ◽  
pp. 47-53 ◽  
Author(s):  
R. E. Forbes ◽  
J. W. Cooper
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Natural Convection ◽  
Hydrodynamic Instability ◽  
Convective Heat Transfer Coefficient ◽  
Free Water ◽  
Ambient Air ◽  
Maximum Density ◽  
Surface Boundary ◽  
Initial Water

Natural convection in horizontal layers of water cooled from above to near freezing was studied analytically. The water was confined laterally and underneath by rigid insulators, and the upper horizontal surface was subjected to: (1) a constant 0C temperature, rigid conducting boundary, and (2) a free, water to air convection boundary condition, in which the convective heat transfer coefficient was held constant at values of 5.68 W/m2 · K and 284 W/m2 · K (1.0 and 50.0 Btu/hr ft2F) and the temperature of the ambient air was maintained at 0C. The ratios of the width to the depth of the rectangular water layers under consideration were W/D = 1, 3, and 6. Initially the water is assumed to be at a uniform temperature of either 4C or 8C, and then the upper surface boundary condition was suddenly applied. It was observed in all cases for which the initial water temperature was 4C, that the water remained stagnant and became thermally stratified. Heat transfer application of either of the surface boundary conditions to water initially at 8C produced large convective eddies extending from the bottom to the top of the layer of water. As the liquid layer cooled further, two distinct horizontal regions appeared, the 4C isothermal line separating the two. This produces a region of hydrodynamic instability in the fluid since the maximum density fluid (4C) is physically located above the less dense fluid in the lower portion of the cavity. The large eddies which appeared initially were confined to the hydrodynamically unstable region bounded by the 4C isotherm and the bottom of the cavity. The action of viscous shearing forces upon the stable water above the 4C isotherm produced a second “layer” of eddies. An alternating direction implicit finite difference method was used to solve the coupled system of partial differential equations. The paper presents transient isotherms and streamlines and a discussion of the effect of maximum density on the flow patterns.

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