On présentera ici des exemples d’études expérimentales d’écoulements diphasiques avec et sans changement de phase pour lesquelles on montrera comment la phase dispersée (vapeur ou gaz) peut modifier la phase porteuse (liquide ou gaz). On s’attachera en particulier à quantifier les modifications des structures de la turbulence dans le cas d’un écoulement turbulent cavitant (de type marche...
Invités Workshop Strasbourg 2023
https://indico.math.cnrs.fr/event/9225/
Conférences invitées:
Sébastien BOYAVAL
Titre : Symmetric-hyperbolic conservation laws to model viscoelastic flows as Maxwell fluids
Abstract: Many Partial Differential Equations (PDEs) have been proposed to model viscoelastic flows. Seminal hyperbolic PDEs have been proposed by Maxwell in 1867 for 2D elastic fluids...
In this talk we present two new classes of structure-preserving schemes for hyperbolic and thermodynamically compatible (HTC) systems with involution constraints, which have been studied for the first time by Godunov in 1961 and later in a series of papers by Godunov & Romenski. In particular, we consider the unified first order hyperbolic model of continuum mechanics proposed by Godunov,...
At very low temperatures (less than 2.17 K), helium becomes superfluid. For instance, it flows through narrow capillaries with no resistance. Although traditional models describe superfluid helium as a mixture of a normal component and a superfluid component, helium is actually a pure substance, not a mixture, that exhibits two motions. In order to describe the two motions, we use geometric...
New conservation laws are obtained for the equations of dispersive continuum mechanics describing Euler–van der Waals–Korteweg’s fluids, fluids containing small gas bubbles, and long–free surface gravity waves (Serre–Green–Naghdi equations). The corresponding mathematical models are characterized by the dependence of the energy on spatial and temporal derivatives of the density. In particular,...
Our goal in this talk is to describe an extension of the arbitrary-rate mechanical relaxation techniques proposed by M. Pelanti [2] for compressible two-phase flows with non-barotropic equations of state to a barotropic two-phase flow, and a hybrid barotropic and non-barotropic two-phase flow. As in [2], we could derive the same first-order ordinary differential equation for the difference in...
I will present our latest developments on the generalization of the Aw-Rascle model of traffic. These include existence and non-uniqueness results and also singular limit analysis leading to certain hard-congestion model. The latter model has been studied in the context of lubrication forces for the motion of rigid bodies in a viscous fluids. The proof of the singular limit will be presented...
Despite the criticism that the Van der Waals theory behind them is too simple, despite the many attempts to replace them with more sophisticated models, despite their well-documented shortcomings, it is a fact that the cubic equations of state (CEoS) are still around, and in industry in particular. Derived from the seminal work of Van der Waals, CEoS appear indeed as reference models for...
