New quantum hydrodynamic equations are derived from a Wigner-Boltzmann model, using the quantum entropy minimization method recently developed by Degond and Ringhofer. The model consists of conservation equations for the carrier, momentum, and energy densities. The derivation is based on a careful expansion of the quantum Maxwellian in powers of the Planck constant. In difference to the standar...

For the development of next-generation GaN-based high electron mobility transistors, reliable software tools for DC and AC simulation are required. A hydrodynamic approach must be used, as the drift diffusion models fail to deliver accurate results for such structures. We propose two different hydrodynamic mobility models which account for the peculiarities of the GaN material system. The model...

We show that, under rather general assumptions on the form of the entropy function, the energy balance equation for a system in thermodynamic equilibrium is equivalent to a set of nonlinear equations of hydrodynamic type. This set of equations is integrable via the method of characteristics and it provides the equation of state for the gas. The shock wave catastrophe set identifies the phase tr...

An alternative process for the design and construction of fluidic devices is presented. Several sealing processes were studied, as well as the hydrodynamic characteristics of the proposed fluidic devices. Manifolds were imprinted on polymeric substrates by direct-write milling, according to Computer Assisted Design (CAD) data. Poly(methyl methacrylate) (PMMA) was used as substrate due to its ph...

Hydrodynamic type systems are systems of quasilinear equations of the first order. They naturally arise in continuum mechanics but also occur as a result of semi-classical approximations of nonlinear dispersive waves. The mathematical theory of one-dimensional hyperbolic quasilinear equations initiated by B. Riemann in XIX century has been developed into a rich and diverse area of applied mathe...

In this paper, three-dimensional two phase turbulent free surface flow is solved by an in-house code. The incompressible Reynolds average Navier-Stocks equations (RANS) with k-ε turbulence model are solved by the finite volume method in the non-orthogonal curvilinear coordinates. For the modeling of the free surface effect, Lagrangian propagation volume tracking method (VOF-PLIC) is used. The c...

This paper addresses an experimental investigation in the hydrodynamic behavior of a modified slotted sieve tray. Slotted sieve tray (Push valve sieve tray) is a sieve tray that the push valves have been utilized on the tray deck to eliminate liquid gradients and non-uniformity of liquid distribution on the tray. The air-water system was used in an industrial scale experimental rig with an inte...

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in coastal areas, hydrodynamic factors make changes in shorelines geomorphology. this can affect coastal facilities and cause hazards to human societies in the areas. this study has investigated the influence of wave and tide properties on khamir port, hormoz strait in coast of persian gulf. the purpose of the study is to make a mathematical regional and local modeling of water level fluctuatio...