Wyniki wyszukiwania - Biblioteka Nauki

1

Transient natural convection between two vertical walls heated/cooled asymmetrically

100%

Singh A. K. , Paul T.

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2006

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tom Vol. 11, no 1

143-154

EN

The present paper analyses a closed form solution for the transient free convective flow of a viscous and incompressible fluid between two vertical walls as a result of asymmetric heating or cooling of the walls. The convection currents between the walls occur due to a change in the temperature of the walls to that of the temperature of the fluid. The Laplace transform method has been used to find the solutions for the velocity and temperature fields by solving the governing partial differential equations. The numerical values obtained from the analytical solution show that the flow is initially in the downward direction near the cooled wall for negative values of the buoyancy force distribution parameter. The temperature field of both the air and water gradually decreases and becomes negative near the cooled wall for all negative values of the buoyancy force distribution parameter. The transient solution approaches a steady state when the non-dimensional time becomes comparable with the actual Prandtl number.

2

Zastosowanie elektrycznego schematu zastępczego do analizy zmian przepływu krwi w nerce

84%

Matulewicz W. , Muc A. , Retkowski M.

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2006

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tom R. 82, nr 6

63-65

PL

Podano podstawę przedstawiania krwiobiegu w postaci przepływu prądu w zastępczym obwodzie elektrycznym. Zasady te zostały zastosowane do odwzorowania krwiobiegu nerki. Istotą badań symulacyjnych z zastosowaniem obwodu elektrycznego jest opracowanie sposobu identyfikacji przyczyn zmian przebiegu prądu, który odwzorowuje przebieg krwi. Jest to bardzo ważne zagadnienie w przypadku diagnostyki nerki po transplantacji umożliwiającej wykrycie zmian stanu krwiobiegu nerki.

EN

Basic principles of showing the blood circulation in the form of current flow in the equivalent circuit were described. These principles have been employed formodeling of the kidney blood circulation. The essence of simulation research with using the electric circuit is a method of the identification of reasons for changes in the current waveform, which the course of blood is copying. This problem is very important in the case of the kidney diagnostic after the transplantation.

3

Exact solutions for incompressible couette flow with constant temperature and constant heat flux on walls in the presence of radiation

84%

Chaudhary R. C. , Jain P.

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2007

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tom Vol. 12, no 4

929-939

EN

The present paper investigates a closed form solution for the transient free convection flow of a viscous incompressible fluid between two infinite vertical paranel plates in the presence of radiation. The flow is set up due to free convective currents occurring as a result of application of a constant heat flux (CHF) at one wall and a constant temperature on the other wall. The Rosseland approximation is used to describe the radiative heat flux in the energy equation. The goveming coupled non-linear partial differential equations have been solved exactly using the Laplace-transform technique. The numerical values obtained from analytical expressions of velocity, temperature, skin-mction and the Nusselt number have been presented graphically to study the behaviour of flow on the momentum and thermal boundary layer.

4

Asymetryczne i odkształcone funkcje przebiegów elektromagnetycznych w transformatorach prostownikowych

84%

Gołębiowski L. , Lewicki J.

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2011

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tom R. 87, nr 8

59-65

PL

Z uwzględnieniem asymetrii i odkształceń przebiegów elektromagnetycznych w zlinearyzowanym transformatorze zasilającym układ prostownikowy, artykuł przedstawia w postaci analitycznej zależności pomiędzy operatorowymi funkcjami przebiegów, jak również uogólniony schemat zastępczy strony wtórnej transformatora. Przedstawione zostało przejście z określonej funkcji operatorowej na postać czasową metodą symboliczną przy pomocy programu Matlab.

EN

Taking into account the asymmetry and distortion of electromagnetic functions in a linearized transformer supplying a rectifier system, the paper presents in analytic form the dependences between operator forms of the functions, as well the generalized equivalent circuit diagram of the transformer secondary site. The transition from determined operator form to the time form with the use of the symbolic method in MATLAB was presented.

5

Transient convective flow of micropolar fluid past a continuously moving vertical porous plate in the presence of radiation

84%

Rahman M. M. , Sattar M. A.

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2007

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tom Vol. 12, no 2

497-513

EN

An unsteady convective flow and heat transfer of a micropolar fluid past a continuously moving verticaI porous plate with time dependent suction and in the presence of radiation has been analyzed numericaIly. With appropriate transformations the boundary layer equations are transformed into a set of nonlinear ordinary differentiaI equations. The locaI similarity solutions in time of the transformed dimensionless equations for the flow, microrotation and the heat transfer characteristics are evaIuated using the Nachtsheim-Swigert shooting iteration technique. NumericaI results are presented in the form of velocity, microrotation and temperature profiles within the boundary layer for different parameters entering into the analysis. FinaIly, the skin friction coefficient and rate of heat transfer are tabulated for the pertinent parameters.