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1
Content available remote Time-periodic thermal boundary effects on porous media saturated with nanofluids : CGLE model for oscillatory mode
Kiran Palle, Manjula Sivaraj H.
Advances in Materials Science
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2022
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Vol. 22, nr 4(74)
98--116
EN
The stability of nonlinear nanofluid convection is examined using the complex matrix differential operator theory. With the help of finite amplitude analysis, nonlinear convection in a porous medium is investigated that has been saturated with nanofluid and subjected to thermal modulation. The complex Ginzburg-Landau equation (CGLE) is used to determine the finite amplitude convection in order to evaluate heat and mass transfer. The small amplitude of convection is considered to determine heat and mass transfer through the porous medium. Thermal modulation of the system is predicted to change sinusoidally over time, as shown at the boundary. Three distinct modulations IPM, OPM, and LBMOhave been investigated and found that OPM and LBMO cases are used to regulate heat and mass transfer. Further, it is found that modulation frequency (ωf varying from 2 to 70) reduces heat and mass transfer while modulation amplitude (δ1varying from 0.1 to 0.5 ) enhances both.
2
Content available The complex Ginzburg Landau model for an oscillatory convection in a rotating fluid layer
Manjula S. H., Kiran P., Reddy P. Raj, Bhadauria B. S.
International Journal of Applied Mechanics and Engineering
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2020
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Vol. 25, no. 1
75--91
EN
A weakly nonlinear thermal instability is investigated under rotation speed modulation. Using the perturbation analysis, a nonlinear physical model is simplified to determine the convective amplitude for oscillatory mode. A non-autonomous complex Ginzburg-Landau equation for the finite amplitude of convection is derived based on a small perturbed parameter. The effect of rotation is found either to stabilize or destabilize the system. The Nusselt number is obtained numerically to present the results of heat transfer. It is found that modulation has a significant effect on heat transport for lower values of ωf while no effect for higher values. It is also found that modulation can be used alternately to control the heat transfer in the system. Further, oscillatory mode enhances heat transfer rather than stationary mode.
3
Content available Chaotic convection of viscoelastic fluid in porous medium under G-jitter
Bhadauria B. S., Singh A., Singh M. K.
International Journal of Applied Mechanics and Engineering
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2019
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Vol. 24, no. 1
37--51
EN
The present article aims at investigating the effect of gravity modulation on chaotic convection of a viscoelastic fluid in porous media. For this, the problem is reduced into Lorenz system (non-autonomous) by employing the truncated Galerkin expansion method. The system shows transitions from periodic to chaotic behavior on increasing the scaled Rayleigh number R. The amplitude of modulation advances the chaotic nature in the system while the frequency of modulation has a tendency to delay the chaotic behavior which is in good agreement with the results due to [1]. The behavior of the scaled relaxation and retardation parameter on the system is also studied. The phase portrait and time domain diagrams of the Lorenz system for suitable parameter values have been used to analyze the system.
4
Content available Weakly nonlinear oscillatory convection in a viscoelastic fluid saturated porous medium with throughflow and temperature modulation
Kiran P., Narasimhulu Y., Manjula S. H.
International Journal of Applied Mechanics and Engineering
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2018
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Vol. 23, no. 3
635--653
EN
The effect of vertical throughfow and temperature modulation on a viscoelastic fluid saturated porous medium has been investigated. The amplitudes of temperature modulation at the lower and upper surfaces are considered to be very small and the disturbances are expanded in terms of power series of amplitude of convection. A weak nonlinear stability analysis has been performed for the oscillatory mode of convection, and heat transport in terms of the Nusselt number, which is governed by the non autonomous complex Ginzburg- Landau equation, is calculated. The effect of vertical through flow is found to stabilize the system irrespective of the direction of through flow in the case of permeable boundary conditions. The time relaxation has a destabilizing effect, while the time retardation parameter has a stabilizing effect on the system. The effects of amplitude and frequency of modulation on heat transport have been analyzed and depicted graphically. The study shows that the heat transport can be controlled effectively by a mechanism that is external to the system. Further, it is also found that heat transfer is more in oscillatory mode of convection rather than in stationary mode of convection.
5
Content available Ruch cieczy w zbiorniku w ruchu obrotowym
Trębacki K., Królicka A.
Autobusy : technika, eksploatacja, systemy transportowe
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2016
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R. 17, nr 10
92--96
PL
W artykule omówiony został ruch ładunku płynnego w zbiorniku podczas obrotu. Przeprowadzono analizę teoretyczną wg teorii liniowej i nieliniowej. Wyznaczono potencjał prędkości cieczy i na tej podstawie funkcję ciśnienia w dowolnym punkcie objętości cieczy w zbiorniku. Podano wykresy obciążeń ścianek zbiornika od cieczy wg obydwu teorii.
EN
The article discussed a motion of liquid cargo in tank during rotation. The conducted are of theoretical analysis according linear and non-linear theory. Was designated the potential of velocity of the liquid and on the basis of pressure function at any point liquid of volume in tank. Are given of load charts walls of tank of liquid according to both theories.
6
Content available Ruch cieczy w zbiorniku poziomym
Trębacki K., Królicka A.
Autobusy : technika, eksploatacja, systemy transportowe
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2016
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R. 17, nr 10
97--102
PL
W artykule omówiony został ruch poziomy zbiornika wypełnionego cieczą. Wymieniono przyczyny ruchu cieczy w zbiorniku. Dokonano analizy wg teorii liniowej i nieliniowej. Wyznaczono częstości drgań własnych. Na podstawie teorii liniowej i nieliniowej wyznaczono funkcję potencjału prędkości Φ i powierzchni swobodnej η. Podano rozkłady ciśnień hydrodynamicznych na ściankach zbiornika.
EN
The article discussed a horizontal motion of tank filled with liquid. Discussed a causes of motion of liquid in the tank. Were made analysis by the theory of linear and nonlinear. In article the given of frequency of vibration. On the basis of theory of linear and nonlinear function are determined velocity potential and free surface. Given of distributions of hydrodynamic pressure on the walls of tank.
7
The effect of nonlinear restraint on torsional buckling and post-buckling behaviour of a thin-walled column
Szymczak C.
Foundations of Civil and Environmental Engineering
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2006
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No. 7
333-342
EN
Torsional buckling and post-buckling of a simply supported axially compressed thin-walled column of open bisymmetric cross-section with a central restrain has been investigated. The nonlinear behaviour of the restraint against the rotation angle of the cross-section has been assumed. The stability consideration is based upon the classical theory of beams with nondeformable cross-section. The solution of the buckling and post-buckling behaviour problem formulated has been found with the perturbation approach. The critical load and the initial post-buckling path of equilibrium for I - column for the cubic relation of the restraint reaction and the rotation angle have been determined. The results show the considerable effect of nonlinearity of the restraint behaviour on the post-buckling path of equilibrium of the column in comparison with the linear restraint.
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