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Ballistic-diffusive heat conduction at nanoscale: GENERIC approach [rapid communication] ; Lebon, Georgy ; Dauby, Pierre et al in Physics Letters A (2005), 339 Heat conduction in nanosize systems has to be studied in settings involving microscopic details that are not seen in the classical Fourier theory. G. Chen has suggested [Phys. Rev. Lett. 86 (2001) 2297] a ... [more ▼] Heat conduction in nanosize systems has to be studied in settings involving microscopic details that are not seen in the classical Fourier theory. G. Chen has suggested [Phys. Rev. Lett. 86 (2001) 2297] a combination of the Cattaneo setting in which the velocity of the heat propagation is finite and the kinetic theory setting in which phonons are seen as heat carriers. In this Letter we show that if the Cattaneo and the kinetic theories are combined in a way that preserves the structure expressing their compatibility with thermodynamics (GENERIC structure) then both the Cattaneo and the kinetic equations become modified. The modified Cattaneo equations involve the term introduced by Chen and, in addition, new terms that are nonlinear in quantities that disappear at equilibrium. The kinetic equation is modified by new terms involving gradients of the heat flux and the local temperature. [less ▲] Detailed reference viewed: 38 (7 ULg)Electrical mapping of spontaneous ventricular fibrillation in acutely ischemic pigs. Desaive, Thomas ; ; et al in Proceedings of the 5th Belgian Day on Biomedical Engineering, 2005, Brussels (2005) Detailed reference viewed: 31 (18 ULg)Closed-loop model of the cardiovascular system including ventricular interaction and valve dynamics: application to pulmonary embolism Desaive, Thomas ; ; Lambermont, Bernard et al in 12th International Conference on Biomedical Engineering (2005) Detailed reference viewed: 36 (4 ULg)Experiments on the role of gas height in the Rayleigh-Marangoni instability problem. ; ; et al in Journal of Colloid & Interface Science (2005), 289(1), 271-5 Experimental evidence is provided to show the effect of gas phase dynamics on the onset of thermal convection and on the accompanying patterns in a silicone oil-air convecting bilayer. Very good agreement ... [more ▼] Experimental evidence is provided to show the effect of gas phase dynamics on the onset of thermal convection and on the accompanying patterns in a silicone oil-air convecting bilayer. Very good agreement with three-dimensional calculations for linearized stability is obtained mostly for small and large gas heights. Reasons for this agreement as well as the results at intermediate gas heights are qualitatively explained from the perspective of well-established nonlinear analysis. [less ▲] Detailed reference viewed: 9 (1 ULg)Improved 1.5-sided model for the weakly nonlinear study of Benard-Marangoni instabilities in an evaporating liquid layer. ; ; Dauby, Pierre in Journal of Colloid & Interface Science (2005), 290(1), 220-30 Benard-Marangoni instability, with coupled gravity and surface tension effects, in an evaporating liquid layer surmounted by its vapor and an inert gas is investigated theoretically. We show that this ... [more ▼] Benard-Marangoni instability, with coupled gravity and surface tension effects, in an evaporating liquid layer surmounted by its vapor and an inert gas is investigated theoretically. We show that this system can be described by a model that consists in the liquid layer equations plus the diffusion equation for the vapor in the gas (the so-called 1.5-sided model) and that this model is equivalent to a one-sided model when the vapor mass fraction field can be considered as quasi-stationary, provided that the equivalent Biot number is a nonlocal function of the interface temperature. A comparison of weakly nonlinear results for the 1.5-sided model with a previous one-sided model [M. Dondlinger, J. Margerit, P.C. Dauby, J. Colloid Interface Sci. 283 (2) (2005) 522-532] that considered a Biot number depending on the wavenumber evaluated at the threshold is performed. Very good agreement is found between both models. For this reason, the present analysis can also be considered as a detailed theoretical justification for the use of a one-sided model in the study of evaporative thermoconvection. [less ▲] Detailed reference viewed: 15 (3 ULg)Approches des phénomènes chaotiques Dauby, Pierre Learning material (2005) Detailed reference viewed: 8 (1 ULg)Weakly nonlinear study of Marangoni instabilities in an evaporating liquid layer ; ; Dauby, Pierre in Journal of Colloid & Interface Science (2005), 283(2), 522-532 Detailed reference viewed: 10 (0 ULg)Stabilité thermomagnétoconvective d'un ferrofluide dans une couche poreuse en rotation Desaive, Thomas ; ; Dauby, Pierre in Mécanique & Industries (2004), 5(5), Detailed reference viewed: 22 (4 ULg)Linear and nonlinear analyses of convective instabilities in evaporating liquid layers ; ; Dauby, Pierre in On Interfacial Fluid Dynamics And Processes in phyisico-chemical systems (2004) An unified extended thermodynamic description of diffusion, thermodiffusion, suspensions and porous media Lebon, Georgy ; Desaive, Thomas ; Dauby, Pierre in Proceedings International Conference on thermal engineering theory and application, Beirut (Liban), 2004 (2004) Detailed reference viewed: 10 (2 ULg)Extended Thermodynamic Description of Thermodiffusive Mass Transport Lebon, Georgy ; Desaive, Thomas ; Dauby, Pierre et al in Proc. 6 th Int. Meeting on Thermodiffusion (IMT6), Varenna, July 2004 (2004) Detailed reference viewed: 18 (2 ULg)Analyse de stabilité linéaire d'un ferrofluide saturant un milieu poreux en rotation Desaive, Thomas ; ; Dauby, Pierre in congrès français de mécanique (2003) Detailed reference viewed: 33 (0 ULg)La thermodiffusion revisitée Lebon, Georgy ; Desaive, Thomas ; Dauby, Pierre in 6ème congrès de mécanique (2003) Detailed reference viewed: 17 (0 ULg)Influence of a nonlinear reference temperature profile on oscillatory Benard-Marangoni convection. ; ; Dauby, Pierre in Physical Review. E : Statistical, Nonlinear, and Soft Matter Physics (2003), 68(6 Pt 2), 066310 We analyze oscillatory instabilities in a fluid layer of infinite horizontal extent, heated from above or cooled from below, taking into account the nonlinearity of the reference temperature profile ... [more ▼] We analyze oscillatory instabilities in a fluid layer of infinite horizontal extent, heated from above or cooled from below, taking into account the nonlinearity of the reference temperature profile during the transient state of heat conduction. The linear stability analysis shows that a nonlinear reference temperature profile can have a strong effect on the system, either stabilizing or destabilizing, depending on the relative importance of buoyancy and surface tension forces. For the nonlinear analysis we use a Galerkin-Eckhaus method leading to a finite set of amplitude equations. In the two-dimensional (2D) case, we show the solution of these amplitude equations are standing waves. [less ▲] Detailed reference viewed: 10 (0 ULg)Stability analysis of Bénard-Marangoni convection in the case of cooling from below ; Dauby, Pierre in Proceedings du 6ème Congrès National de Mécanique théorique et appliquée (NCTAM-2003), Gent (Belgium), 26-27 may 2003 (2003) Detailed reference viewed: 6 (0 ULg)Convection de Bénard-Marangoni en régime oscillant ; Dauby, Pierre in Proceedings du 16ème Congrès français de mécanique, Nice, 1-5 septembre 2003 (2003) Detailed reference viewed: 8 (1 ULg)Application of the laser beam deflection to the study of temperature filed and heat transfer in natural convection, ; ; Dauby, Pierre in Experiments in Fluids (2002), 33 Detailed reference viewed: 10 (0 ULg)Generalized Fourier equations and thermoconvective instabilities Dauby, Pierre ; ; Lebon, Georgy in Revista Mexicana De Fisica (2002), 48(Suppl. 1), 57-62 Detailed reference viewed: 12 (7 ULg)Amplitude equations for Rayleigh-Benard convective rolls far from threshold Dauby, Pierre ; Desaive, Thomas ; et al in Physical Review E (2001), 64(6), 66301 An extension of the amplitude method is proposed. An iterative algorithm is developed to build an amplitude equation model that is shown to provide precise quantitative results even far from the linear ... [more ▼] An extension of the amplitude method is proposed. An iterative algorithm is developed to build an amplitude equation model that is shown to provide precise quantitative results even far from the linear instability threshold. The method is applied to the study of stationary Rayleigh-Benard thermoconvective rolls in the nonlinear regime. In particular, the generation of second and third spatial harmonics is analyzed. Comparison with experimental results and direct numerical calculations is also made and a very good agreement is found. [less ▲] Detailed reference viewed: 52 (7 ULg)The influence of gas depth on interfacial convection in a liquid gas bilayer. ; ; et al in Bulletin of the American Physical Society, Proceedings of the 54th Annual Meeting of the APS Division of Fluid Dynamics (2001, November 01) We present a study of the influence of air height on the pattern formation at the onset of interfacial convection in a liquid -gas bilayer. Bilayer convection results from interaction of two immiscible ... [more ▼] We present a study of the influence of air height on the pattern formation at the onset of interfacial convection in a liquid -gas bilayer. Bilayer convection results from interaction of two immiscible, superposed fluid layers and it is a transport problem that is affected by the ratios of various thermophysical properties and geometries. By using both calculations and experiments, a new convection-coupling mechanism is revealed. When the gas depth is low the convection is dominant in the liquid. It is of the Rayleigh Marangoni type and subcritical convection may be seen for axisymmetric patterns at the onset. For large gas heights the convection in the upper fluid layer simultaneously generates transverse thermal gradients along the fluid-fluid interface immediately causing surface tension gradient and buoyancy driven-convection in the lower fluid. The convection in the gas is of the Rayleigh type and the self-adjoint nature of the mathematical problem is depicted in the experiment wherein no subcritical motion occurs. In both the calculations and the experiment, silicone oil and air were used as the two fluids. As the viscosity of air is quite low compared to the silicone oil, convection in the air has no mechanical influence on the silicone oil and it is this property that is advantageous in isolating the new convection mechanism. The correspondence between theory and experiment is excellent. [less ▲] Detailed reference viewed: 11 (0 ULg) |
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