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Very recently, driven by glassmakers and champagne houses, attention has been paid to the way to control effervescence and bubble nucleation. It was demonstrated that ascending bubbles act like many swirling motion generators in champagne glasses. It is the reason why a numerical modeling of flow dynamics induced by the effervescence in a glass of champagne has been carried out for the first time using the finite volume method by Computational Fluid Dynamics (CFD). The paper aims to discuss these issues.

In order to define source terms for flow regime and to reproduce accurately the nucleation process at the origin of effervescence, specific subroutines for the gaseous phase have been added to the main numerical model. These subroutines allow the modeling of bubbles behavior based on semi-empirical formulas relating to bubble diameter and velocity or mass transfer evolutions.

Details and development of the steps of modeling are presented in this paper, showing a good agreement between the results obtained by CFD simulations in a reference case of those from laser tomography and Particle Image Velocimetry experiments, validating the present model.

A numerical modeling of flow dynamics induced by the effervescence in a glass of champagne has been carried out for the first time using the finite volume method by CFD.

In the present work, a theoretical model based on the full Navier-Stokes and energy equations for transient mixed convection in a vertical tube is extended to nanofluids with nanoparticle volume fraction up to 5 percent to ensure a Newtonian fluid behaviour. The paper aims to discuss these issues.

The nanofluids considered, alumina/water and CuO/water, flow inside a vertical tube of circular cross-section, which is subjected to convective heat exchange at the outer surface. The transient regime is caused by a sudden change of nanofluid temperature at the tube inlet. The range of the Richardson number (1.6=Ri=2.5) investigated in this study corresponds to classic cases of mixed convection flow.

Results have shown a significant reduction in the size of the recirculation zone near the wall when the particle volume fraction increases. This may be attributed to the viscosity increase with the volume fraction. Moreover, the flow structure clearly changes when the convective heat transfer coefficient is modified. A decrease of the wall temperature along the tube was found when increasing the convective heat transfer coefficient imposed at the tube external surface.

The problem formulation in 2D axisymmetric geometry includes the continuity, the Navier-Stokes and energy equations and is based on the stream function and vorticity; the numerical solution of equations is carried out using a finite difference method.

From an economic point of view, this research paper is innovative in the sense that it considers nanofluids as a new and more efficient way to transfer heat. This paper could find applications for heat exchange purposes of compact systems with high thermal loads.

Across the world, a still growing number of research teams are investigating nanofluids and their properties. Investigations concern several aspects such as the preparation of the nanofluids, as well as the applications of these nanofluids for convective heat transfer purposes. The dynamical study will consist in the instantaneous and spatial characterization of the dynamic flow field for different nanoparticle volume fractions.