On a boundary value problem for an equation of the type of non-stationary filtration
Analyzing the validity and success of a data assimilation algorithmwhen some state variable observations are not available is an important problem in meteorology and engineering. We present an improved data assimilation algorithm for recovering the exact full reference solution (i.e. the velocity and temperature) of the 3D Planetary Geostrophic model, at an exponential rate in time, by employing coarse spatial mesh observations of the temperature alone. This provides, in the case of this paradigm,...
We consider a one-dimensional incompressible flow through a porous medium undergoing deformations such that the porosity and the hydraulic conductivity can be considered to be functions of the flux intensity. The medium is initially dry and we neglect capillarity, so that a sharp wetting front proceeds into the medium. We consider the open problem of the continuation of the solution in the case of onset of singularities, which can be interpreted as a local collapse of the medium, in the general...
The Muskat problem models the dynamics of the interface between two incompressible immiscible fluids with different constant densities. In this work we prove three results. First we prove an maximum principle, in the form of a new “log” conservation law which is satisfied by the equation (1) for the interface. Our second result is a proof of global existence for unique strong solutions if the initial data is smaller than an explicitly computable constant, for instance . Previous results of this...
In this paper we present an analysis of the partial differential equations that describe the Chemical Vapor Infiltration (CVI) processes. The mathematical model requires at least two partial differential equations, one describing the gas phase and one corresponding to the solid phase. A key difficulty in the process is the long processing times that are typically required. We address here the issue of optimization and show that we can choose appropriate pressure and temperature to minimize these...
Si considera l'insorgere della convezione naturale in un mezzo poroso (Horton-Rogers-Lapwood problem), assumendo che la viscosità del fluido dipenda dalla temperatura. Adoperando il metodo diretto di Liapunov, si effettua l'analisi della stabilitá non lineare della soluzione di conduzione per i modelli di Darcy e di Forchheimer.