Wyniki wyszukiwania - Biblioteka Nauki

1

ALE method in the fluid-structure interactions

100%

Křen J. , Žán J.

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tom z. 19

101-104

EN

The paper deals with an approach to the solution of the coupled fluid-structure interaction problem, where a viscous incompressible fluid and a rigid body-spring system interact with each other. In order to incorporate the effect of the moving surface of the rigid body, the arbitrary Lagrangian-Eulerian formulation is employed as the basis of the finite element spatial discretization. The semi-coupled numerical method is then used for the time integration of the equations of the motion.

2

Inertia effects in a curvilinear thrust hydrostatic bearing with a porous pad

100%

Walicka A. , Jurczak P. , Walicki E.

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tom Vol. 15, no 4

1227-1238

EN

The flow of a Newtonian lubricant in a clearance of a curvilinear thrust hydrostatic bearing with one porous wall is considered. The bearing is modelled by two curvilinear smooth surfaces and the porous wall is adhered to the curve non-porous surface. The flow in the bearing clearance is considered with inertia forces and the Navier-Stokes and Poisson equations are uncoupled by using the Morgan-Cameron approximation. The equations of motion are solved by an averaged inertia method. Step and spherical bearings are discussed as examples. It shown that the inertia effects influence the bearing performance considerably.

3

Wytwarzanie zawiesiny cząstek ciała stałego w lepkiej cieczy w mieszalniku zaopatrzonym w niestandardowe przegrody

84%

Karcz J. , Więch D.

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tom Z. 27

131-138

PL

Przeprowadzono doświadczalne badania warunków wytwarzania zawiesiny cząstek ciała stałego w cieczy niutonowskiej o znacznie większej lepkości niż woda w mieszalniku wyposażonym w niestandardowe, krótkie przegrody i mieszadło turbinowe tarczowe. Na podstawie tych badań określono krytyczne częstości obrotów mieszadła dla każdej z testowanych konfiguracji przegród w mieszalniku.

EN

Experimental studies of the suspending of the particles in a viscous Newtonian liquid were carried out in the agitated vessel of diameter D = 0.3 m equipped with Rushton disc turbine and nonstandard baffles of length L (where L + p = H). On the basis of the measurements, critical impeller speeds nkr were determined for each configurations of the baffles tested. The results of the studies show that critical impeller speeds decrease with the increase of the geometrical parameter p/H and slightly only depend on the liquid viscosity within the range of the low mean concentration of the particles in the liquid.

4

Analytical modelling for Newtonian fluid flow through an elastic tube

84%

Mehdari A. , Agouzoul M. , Hasnaoui M.

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tom Vol. 19, No. 1

57--62

EN

The objective of the present work is to develop analytical modelling of an unsteady fluid flow through an elastic tube. The fluid is considered to be Newtonian and incompressible. The cylindrical tube wall boundaries are isotropic. The study provides a review of recent modelling aimed at understanding the effects of fluid parameters over the elastic tube wall behaviour. First of all, the fluid flow is analysed following an asymptotic approach according to a large Reynolds number and a small aspect radio. Second of all, the wall has been assumed to be a thin shell, which generates a small axisymmetric vibration. The mathematical model is developed according the thin shell theory. The dynamic behaviour of the tube wall is represented and discussed.

5

Wpływ sprężystych właściwości oleju smarującego na parametry filmu olejowego na gładzi cylindrowej silnika spalinowego

84%

Jakubiak L. , Serdecki W.

Journal of KONES

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2000

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tom Vol. 7, No. 1-2

199-206

PL

W dotychczas budowanych modelach matematycznych układu tłokowo-cylindrowego, w części ujmującej wpływ oleju smarującego, uwzględniano przede wszystkim jego lepkość. Postępowanie takie było poprawne przy założeniu, że olej smarujący ma właściwości cieczy idealnie lepkiej (cieczy newtonowskiej). W ostatnich latach pojawiła się duża liczba nowych, syntetycznych olejów smarujących, których właściwości mogą znacznie odbiegać od tego typu cieczy. Wymusza to konieczność uwzględnienia w modelu matematycznym nowych jego cech, w tym w szczególności jego sprężystości. W opracowaniu podano informacje o zjawiskach występujących podczas przepływu cieczy lepkosprężystych oraz ich wpływie na podstawowe parametry filmu olejowego, ze szczególnym uwzględnieniem sił tarcia.

EN

In so far built mathematical models of piston-cylinder system, first of all the oil viscosity is taken into account in the part considering an effect of lubricating oil. Such procedure is correct if the lubricating oil has properties of a Newtonian fluid. Recently, a large number of new synthetic lubricating oils have appeared on the market. Their properties differ considerably from those of mineral oils. The need for introduction of theirs properties into the mathematical model appeared, particularly elasticity. Data on phenomena emerging during the flow of viscoelastic fluids and their influence on basic parameters of oil film are presented in this study with special interest paid for friction power.

6

A new analytical procedure for solving the non-linear differential equation arising in the stretching sheet problem

84%

Siddheshwar P. G. , Mahabaleswar U. S. , Andersson H. I.

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tom Vol. 18, no. 3

955--964

EN

The paper discusses a new analytical procedure for solving the non-linear boundary layer equation arising in a linear stretching sheet problem involving a Newtonian/non-Newtonian liquid. On using a technique akin to perturbation the problem gives rise to a system of non-linear governing differential equations that are solved exactly. An analytical expression is obtained for the stream function and velocity as a function of the stretching parameters. The Clairaut equation is obtained on consideration of consistency and its solution is shown to be that of the stretching sheet boundary layer equation. The present study throws light on the analytical solution of a class of boundary layer equations arising in the stretching sheet problem.