1,721,080 research outputs found
Progettazione termo-fluido-dinamica del sistema galleria: ventilazione della struttura e comportamento termico dei materiali
No full textThermodynamically consistent formulation of a deterministic non equilibrium theory of non homogeneous media
No full text
Proceedings of 70-th Eurotherm Seminar, "Physical and Mathematical Modelling of Fires in Enclosures and Fire Protection", Torino, 2002
No full text
Thermal instability of viscoelastic fluids in horizontal porous layers as initial value problem
No full textThe instability of a viscoelastic fluid saturating a horizontal porous layer heated from below is studied theoretically with a dynamical system approach. The viscoelastic character of the flow is taken into account by a modified Darcy's law. The conservation equations of mass, momentum and energy are approximated by a reduced-order system of nonlinear, ordinary differential equations, which is similar to the well-known system derived by Lorenz to describe atmospheric convection. Equilibrium points and their stability are expressed as functions of a dimensionless heat capacity and of two relaxation parameters. Qualitative expressions of the Nusselt number when the system is out of equilibrium are also derived
Geometric approach to laminar convection
No full textThe analytical approach to the solution of a steady-state convection problem for Hagen-Poiseuille flow in tubes of arbitrary cross section was analyzed. The problem was studied in the view of isoperimetric inequalities, that is of inequalities holding for domain functionals, provided that equality is attained. The formal analogy with continuum solid mechanics allowed to develop a semiqualitative theory of laminar convection in tubes of arbitrary cross section. The heat transfer rate per unit length across the wall can be expressed in terms of a geometric parameter for a fluid of constant shear viscosity. The heat transfer rate could be calculated in terms of overall quantities without requiring pointwise solution of the Hagen-Poiseuille problem
- …
