The effect of the thickness of the porous material on the parallel plate channel flow when the walls are provided with non-erodible porous lining

Flow through a channel whose walls are lined with non-erodible porous material is investigated using Beavers and Joseph slip boundary condition. It is shown that the effect of porous lining is to increase the mass flow rate and to decrease the friction factor.     

Flow of viscous stratified fluid of variable viscosity past a porous bed

To study the effects of stratification and slip velocity on the flow of fluid of variable viscosity over a permeable bed, we divide the flow into two zones called zone 1 and zone 2. Zone 1 pertains to the flow called the free flow governed by the Navier-Stokes equations in the region between the impermeable upper plate and the porous bed.. Zone 2 pertains to the flow in the bed governed by the modified Darcy Law. Using the slip velocity boundary condition, velocity distributions in zones 1 and 2 are obtained and are matched at the interface. The boundary layer thickness just beneath the permeable interface and the friction factor are also obtained.     

Convective heat transfer in a parallel plate channel with porous lining

The paper proposes a theoretical model for the study of flow and heat transfer in a parallel plate channel, one of whose walls is lined with non-erodible porous material, both the walls being kept at constant temperatures. The analysis uses Brinkman model in the porous medium and employs the velocity and temperature slips at the interface (the so called nominal surface). The influence of the thickness as well as the permeability of the porous medium on the flow field and Nusselt numbers at the walls is investigated.

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Konvektive Wärmeübertragung in einem Parallelplattenkanal mit porösem Überzug

Zusammenfassung Die vorliegende Arbeit befaßt sich mit dem Vorschlag eines theoretischen Modells, um die Wärmeübertragung in einem Parallelplattenkanal mit unauswaschbarem porösem Überzug zu studieren. Die Strömung innerhalb des porösen Überzugs ist mit Hilfe der Brinkmannschen Gleichung analysiert. An der Grenze (der sogenannten Nominalfläche) zwischen dem Überzug und der freien Strömung sind die Geschwindigkeitsgleitung und die Temperaturgleitung benutzt. Die Beeinflussung des Geschwindigkeitsfelds und die Nusseltschen Zahlen an den Wänden in Abhängigkeit von der Dicke und der Durchlässigkeit des porösen Überzugs ist untersucht.

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Nomenclature u streamwise velocity in Zone 1 (Fig. 1) - û streamwise velocity in Zone 2 (Fig. 1) - p pressure - coefficient of viscosity of the fluid - k absolute permeability of the material used for lining - density of the fluid - R Reynolds number - the average velocity in Zone 1 (Fig. 1) - T temperature in Zone 1 (Fig. 1) - T temperature in Zone 2 (Fig. 1) - K thermal conductivity in Zones 1 and 2 (Fig. 1) - M ₁ non-dimensional mass flow rate in Zone 1 (Fig. 1) - M ₂ non-dimensional mass flow rate in Zone 2 (Fig. 1) - (Nu)_U Nusselt number at the upper plate (Fig. 1) - (Nu) _L Nusselt number at the lower plate (Fig. 1) - _E experimental value of the temperature in the channel (with porous lining) at a specified point - _E/* experimental value of the temperature in the channel (without porous lining) at a specified point     

Stability of viscous flow in a rotating porous medium in the form of an annulus: The small-gap problem

The paper deals with the linear stability analysis of laminar flow of a viscous fluid in a rotating porous medium in the form of an annulus bounded by two concentric circular impermeable cylinders. The usual no-slip condition is imposed at both the boundaries. The resulting sixth order boundary value, eigenvalue problem has been solved numerically for the small-gap case by the Runge-Kutta-Gill method, assuming that the marginal state is stationary. The results of computation reveal that the critical Taylor number increases with decreasing permeability of the medium. The problem is found to reduce to the case of ordinary viscous flow in the annulus obtained by Chandrasekhar,¹ when the permeability parameter tends to zero.     

Study on activity of radium,radon and physicochemical parameters in ground water and their health hazards around Tumkur industrial area

Journal of Radioanalytical and Nuclear Chemistry - The activity of radium (226Ra), radon (222Rn) and physicochemical parameters in ground water around study area were estimated by standard...     

Studies on radon/thoron and their decay products in granite quarries around Bangalore city, India

The radon survey was performed in granite quarries around Bangalore rural district and Bangalore city as part of a lung cancer epidemiological study. Long duration measurements of indoor and outdoor radon, thoron and their progenies concentrations were made around granite quarries of Bangalore rural district by using Solid State Nuclear Track Detector (SSNTD, LR-115, Type-II Plastic track detector) during summer and winter period (2006–07). The increase of radioactivity in granite quarries and inhalation dose to workers and populations near the quarries have been summarized. The higher concentrations of radon and thoron in granite quarries suggest radiation health effects on workers and public around the quarries is higher than permissible levels. The results are presented and analyzed with reference to ICRP limits.     

Furanverbindungen, 14. Mitt.

Zusammenfassung Eine für die Synthese linearer Furoxanthone ohne Substituenten am Furanring geeignete Methode ist dieUllmann-Kondensation von 6-Hydroxycumaran mit verschiedenen o-Chlorbenzoesäuren mit anschließender Cyclisierung und Dehydrierung. Als Beispiele werden die Synthesen von Furo[3,2-b]-, 7-Methylfuro-[3,2-b]-und 8-Methylfuro[3,2-b]xanthon beschrieben.

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A method for the synthesis of linear furoxanthones carrying no substituent in the furan ring is achieved by theUllmann condensation of 6-hydroxycoumaran with various o-chlorobenzoic acids, followed by cyclisation and subsequent dehydrogenation. This is illustrated by the synthesis of furo[3,2-b]-, 7-methylfuro[3,2-b]-and 8-methylfuro[3,2-b]xanthones.

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Diese Veröffentlichung ist ein Teil der Dissertation, dieC. S. Angadiyavar an der Karnatak University zur Erlangung des Titels eines Ph. Dr. einreichen wird.

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10. Mitt.:Y. S. Agasimundin undS. Rajagopal, Chem. Ber.100, 383 (1967).