A. Sarkar

Bio: A. Sarkar is an academic researcher from Jadavpur University. The author has contributed to research in topics: Heat transfer & Natural convection. The author has an hindex of 3, co-authored 4 publications receiving 202 citations.

Effect of thick horizontal partial partition attached to one of the active walls of a differentially heated square cavity

Abstract: The effect of a partial horizontal partition plate of finite thickness, attached to the heated vertical wall of a differentially heated square cavity, has been studied numerically using the finite element method. The partition thickness is varied from 0.5% of the height of the cavity to 10%. The partition is considered to be located at the middle of the hot wall of a width equivalent to 20% of the cavity width. It is observed that as the partition thickness is reduced, heat transfer across the cavity decreases at first, until a critical thickness of the partition plate is reached. Beyond this value, heat transfer increases as the thickness of the partition is further reduced. Streamline maps are found to be notably sensitive to the partition thickness. The effect of conductivity of the partition material on heat transfer is also studied. Except for material with poor thermal properties, conductivity of the partition is observed to have a negligible effect on heat transfer.

On the effect of porous thick horizontal partial partition attached to one of the active walls of a differentially heated square cavity

Abstract: The effect of a horizontal partial porous partition on heat transfer and flow structure in a differentially heated square cavity is investigated. While the fluid flow is assumed to be governed by Navier—Stokes equations, fluid saturated porous media is assumed to be governed by Darcy’s equations. Standard Galerkin method of finite element formulation is applied for discretization of the system of equations. The non‐linearities in the discretized equations are treated with Newton‐Raphson scheme. The code developed is tested for validation for modified Rayleigh number Ra up to 400. The code is then applied to a differentially heated square cavity with a horizontal partial porous partition. While the thickness of the porous partition is found to have appreciable effect on heat transfer and flow field, width of the porous partition is found to have insignificant bearing on heat transfer except when the partition is very small and compatible to the thickness of the boundary layer developed. During the experime...

Active and Passive Controls of Nanoparticles in Bioconvection Nanofluid Flow Containing Gyrotactic Microorganisms

Abstract: The present work deals with an investigation for the bioconvective flow of nanofluid containing gyrotactic microorganisms over a permeable stretching surface embedded in a non-Darcy porous medium. Two varied cases of controlling nanoparticles say active and passive control have been studied. By introducing a similarity transformation, the governing boundary layer equations are converted into non-linear ordinary equations with pertinent boundary conditions and then solved numerically by a powerful programming MAPLE-18 which includes RK-4 method accompanied by shooting criteria. It is remarkably observed that the fluid velocity is decreased for the increasing value of the porosity parameter while it increases the fluid temperature for both types of control. Also, the present results divulge that the rate of heat transfer in the passive control model is remarkably higher than the active control model whereas the mass flux at the wall for the passive control model is lesser than the active control model.

Laminar Natural Convection Heat Transfer in a Differentially Heated Square Cavity Due to a Thin Fin on the Hot Wall

Abstract: A finite-volume-based computational study of steady laminar natural convection (using Boussinesq approximation) within a differentially heated square cavity due to the presence of a single thin fin is presented. Attachment of highly conductive thin fins with lengths equal to 20, 35 and 50 percent of the side, positioned at 7 locations on the hot left wall were examined for Ra=10 4 , 10 5 , 10 6 , and 10 7 and Pr=0.707 (total of 84 cases). Placing a fin on the hot left wall generally alters the clockwise rotating vortex that is established due to buoyancy-induced convection. Two competing mechanisms that are responsible for flow and thermal modifications are identified. One is due to the blockage effect of the fin, whereas the other is due to extra heating of the fluid that is accommodated by the fin. The degree of flow modification due to blockage is enhanced by increasing the length of the fin. Under certain conditions, smaller vortices are formed between the fin and the top insulated wall