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Search Results: 1 - 10 of 3559 matches for " Rabindra Nath Jana "
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Unsteady Couette Flow through a Porous Medium in a Rotating System  [PDF]
Maitree Jana, Sanatan Das, Rabindra Nath Jana
Open Journal of Fluid Dynamics (OJFD) , 2012, DOI: 10.4236/ojfd.2012.24016
Abstract: An investigation has been made on an unsteady Couette flow of a viscous incompressible fluid through a porous me- dium in a rotating system. The solution of the governing equations has been obtained by the use of Laplace transform technique. It is found that the primary velocity decreases and the magnitude of the secondary velocity increases with an increase in rotation parameter. The fluid velocity components are decelerated by an increase of Reynolds number. An increase in porosity parameter leads to increase the primary velocity and the magnitude of the secondary velocity. It is also found that the solution for small time converges more rapidly than the general solution. The asymptotic behavior of the solution is analyzed for small as well as large values of rotation parameter and Reynolds number. It is observed that a thin boundary layer is formed near the moving plate of the channel and the thicknesses of the boundary layer increases with an increase in porosity parameter.
Radiative Heat Transfer of an Optically Thick Gray Gas in The Presence of Indirect Natural Convection  [PDF]
Rabindra Nath Jana, Swapan Kumar Ghosh
World Journal of Mechanics (WJM) , 2011, DOI: 10.4236/wjm.2011.12009
Abstract: We study the effects of thermal radiation of a viscous incompressible fluid occupying a semi-infinite region of space bounded by an infinite horizontal moving hot flat plate in the presence of indirect natural convection by way of an induced pressure gradient. The fluid is a gray, absorbing emitting radiation but a non scattering medium. An exact solution is obtained by employing Laplace transform technique. Since temperature field depends on Reynold number the flow is considered to be non-isothermal case (the temperature of the plate Tw ≠ constant) and for an isothermal case (Tw = constant) the flow is determined by the Reynold number which is equal to 1.
Radiation Effects on Free Convection MHD Couette Flow Started Exponentially with Variable Wall Temperature in Presence of Heat Generation  [PDF]
Sanatan Das, Bhaskar Chandra Sarkar, Rabindra Nath Jana
Open Journal of Fluid Dynamics (OJFD) , 2012, DOI: 10.4236/ojfd.2012.21002
Abstract: Radiation effects on free convection MHD Couette flow started exponentially with variable wall temperature in the presence of heat generation have been studied. The governing equations are solved analytically using the Laplace transform technique. The variations of velocity and fluid temperature are presented graphically. It is observed that the velocity decreases with an increase in either magnetic parameter or radiation parameter or Prandtl number. It is also observed that the velocity increases with an increase in either heat generation parameter or Grashof number or accelerated parameter or time. An increase in either radiation parameter or Prandtl number leads to fall in the fluid temperature. It is seen that the fluid temperature increases with an increase in either heat generation parameter or time. Further, it is seen that the shear stress at the moving plate decreases with an increase in either magnetic parameter or radiation parameter while it increases with an increase in either heat generation parameter or Prandtl number. The rate of heat transfer increases with an increase in either Prandtl number or time whereas it decreases with an increase in heat generation parameter.
Combined Effects of Hall Current and Radiation on MHD Free Convective Flow in a Vertical Channel with an Oscillatory Wall Temperature  [PDF]
Sankar Kumar Guchhait, Sanatan Das, Rabindra Nath Jana
Open Journal of Fluid Dynamics (OJFD) , 2013, DOI: 10.4236/ojfd.2013.31002
Abstract: The combined effects of Hall current and radiation on an unsteady MHD free convective flow of a viscous incompressible electrically conducting fluid in a vertical channel with an oscillatory wall temperature have been studied. We have considered two different cases 1) flow due to the impulsive motion of one of the channel walls and 2) flow due to the accelerated motion of one of the channel walls. The governing equations are solved analytically using the Laplace transform technique. It is found that the primary velocity and the magnitude of the secondary velocity increase with an increase in Hall parameter for both the impulsive as well as the accelerated motions of one of the channel walls. An increase in either radiation parameter or frequency parameter leads to decrease in the primary velocity and the magnitude of the secondary velocity for both the impulsive as well as accelerated motions of one of the channel walls. The fluid temperature decreases with an increase in radiation parameter. Further, the shear stresses at the left wall reduce with an increase in either radiation parameter or frequency parameter for both the impulsive as well as the accelerated motions of one of the channel wall.
Effects of Radiation on MHD Natural Convection Near a Vertical Plate with Oscillatory Ramped Plate Temperature
Maitree Jana,Sanatan Das,Rabindra Nath Jana
International Journal of Engineering Innovations and Research , 2012,
Abstract: The effects of radiation on the MHD flow past a vertical plate with oscillatory ramped plate temperature in the presence of a uniform transverse applied magnetic field have been investigated. An analytical solution of the governing equations has been obtained by employing Laplace transform technique. The numerical results for fluid velocity and temperature are presented graphically. It is found that an increase in radiation parameter leads to decrease the fluid velocity and temperature. It is also found that both the velocity as well as the temperature of the fluid decrease with an increase in Prandtl number. It is found that the shear stress due to the flow decreases with an increase in magnetic parameter while it increases with an increase in radiation parameter. Further, the rate of heat transfer at the plate increases with an increase in radiation parameter.
UNSTEADY FREE CONVECTIVE FLOW PAST A MOVING VERTICAL POROUS PLATE WITH NEWTONIAN HEATING
SANKAR KUMAR GUCHHAIT,SANATAN DAS,RABINDRA NATH JANA
International Journal of Engineering Science and Technology , 2012,
Abstract: The unsteady free convective flow past a vertical porous plate with Newtonian heating has been studied. The governing equations have been solved numerically by Crank-Nicolson implicit finite-difference scheme. The variations of velocity and fluid temperature are presented graphically. It is found that the fluid velocity decreases with an increase in Prandtl number. Both the fluid velocity and the fluid temperature increase with an increase in suction parameter. An increase in Grashof number leads to rise in the fluid velocity. Further, it is observed that the shear stress and the rate of heat transfer at the plate increase with an increase in either Prandtlnumber or suction parameter or time.
Combined Effects of Hall Currents and Rotation on Steady Hydromagnetic Couette Flow
Bhaskar Chandra Sarkar,Sanatan Das,Rabindra Nath Jana
Research Journal of Applied Sciences, Engineering and Technology , 2013,
Abstract: We study a steady hydromagnetic Couette flow of a viscous incompressible electrically conducting fluid in a rotating system between two infinitely long parallel plates in the presence of a uniform transverse magnetic field on taking Hall Current into account. The governing equations describing the flow are solved analytically. It is observed that the Hall currents accelerate the primary velocity whereas they retard the secondary velocity. The induced magnetic field is significantly affected by the Hall currents. An increase in Hall currents leads to fall in the fluid temperature. The heat transfer characteristics have also been studied. The rate of heat transfer at the lower plate decreases whereas the rate of heat transfer at the upper plate increases with an increase in Hall parameter. The asymptotic behavior of the solutions are discussed for small and large values of magnetic parameter and rotation parameter. It is interesting to note that either for strong magnetic field or for large rotation there exists a single-deck boundary layer in the region near the stationary plate. The thickness of this boundary layer first decreases, reaches a minimum and then increases with an increase in Hall parameter.
Provenance Variability during Damuda Sedimentation in the Talchir Gondwana Basin, India – A Statistical Assessment  [PDF]
Rabindra Nath Hota, Bijay Kumar Das, Madhusmita Sahoo, Wataru Maejima
International Journal of Geosciences (IJG) , 2011, DOI: 10.4236/ijg.2011.22013
Abstract: The Talchir Gondwana basin houses the Talchir Formation at the base, succeeded by the Damuda Group and the Kamthi Formation in upward progression. The present study is an attempt to determine the provenance of the Damuda Group and its variability in terms of location, climate and tectonism through time from the composition of sandstone grains and detritus of the constituent Karharbari, Barakar and Barren Measures formations. The Damuda sandstones are composed of variable amounts of monocrystalline undulatory, nonundulatory and polycrystalline quartz grains, potash and plagioclase feldspars as well as metamorphic and sedimentary rock fragments in addition to heavy accessories. Palaeocurrent studies suggest that the Eastern Ghats Supergroup lying to the south of the basin served as the source area of the Damuda sediments. Plots of sandstone composition in tectonic setting discrimination diagrams suggest derivation of the detritus from craton interior, continental block and recycled orogen provinces. Statistical analyses indicate significant differences in the detrital modes of the sandstones of the Karharbari, Barakar and Barren Measures formations, which may be attributed to temporal and spatial variation of the provenance coupled with climate change in commensurate with Damuda sedimentation.
Cyclic Sedimentation of the Barakar Formation, Singrauli Coalfield, India: Statistical Assessment from Borehole Logs  [PDF]
Rabindra Nath Hota, Pallavi Chatterjee Adhikari, Anketika Mohanty, Wataru Maejima
Open Journal of Geology (OJG) , 2012, DOI: 10.4236/ojg.2012.21001
Abstract: The succession of lithofacies of a part of the Barakar Formation of the Singrauli coalfield has been studied by statistical techniques. The lithologies have been grouped under five facies states viz. coarse-, medium-, and fine-grained sandstones, shale and coal for statistical analyses. Markov chain analysis indicates the arrangement of Barakar lithofacies in the form of fining-upward cycles. A complete cycle consists of conglomerate or coarse-grained sandstone at the base sequentially succeeded by medium- and fine-grained sandstones, shales and coal seam at the top. The entropy analysis puts the Barakar cycles in A-4 type of cyclicity, which consists of different proportions of lower-, side- and upper-truncated cycles of lithologic states. Regression analysis indicates a sympathetic relationship between total thickness of strata (net subsidence) and number of coal cycles and an antipathic relationship between average thickness and number of coal cycles. The cyclic sedimentation of the Barakar Formation was controlled by autocyclic process, which occurred due to the lateral migration of streams triggered by intrabasinal differential subsidence. In many instances, the clastic sediments issued from the laterally migrating rivers interrupted the sedimentation resulting in thinner cycles in areas where the numbers of cycles are more. Principal component and multivariate regression analyses suggest that the net subsidence of the basin is mostly controlled by number and thickness of sandstone beds and coal seams.
Combined Effects of Centrifugal and Coriolis Instability of the Flow through a Rotating Curved Duct with Rectangular Cross Section  [PDF]
Rabindra Nath Mondal, Samir Chandra Ray, Shinichiro Yanase
Open Journal of Fluid Dynamics (OJFD) , 2014, DOI: 10.4236/ojfd.2014.41001
Abstract: Combined effects of centrifugal and coriolis instability of the flow through a rotating curved duct with rectangular cross section have been studied numerically by using a spectral method, and covering a wide range of the Taylor number  for a constant Dean number. The rotation of the duct about the center of curvature is imposed in the positive direction, and the effects of rotation (Coriolis force) on the flow characteristics are investigated. As a result, multiple branches of asymmetric steady solutions with two-, three-and multi-vortex solutions are obtained. To investigate the non-linear behavior of the unsteady solutions, time evolution calculations as well as power spectrum of the unsteady solutions are performed, and it is found that the unsteady flow undergoes through various flow instabilities in the scenario “chaotic → multi-periodic → periodic → steady-state”, if Tr is increased in the positive direction. The present results show the characteristics of both the secondary flow and axial flow distribution in the flow.
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