Rarefied gas flows in channels, pipes, and ducts with smooth surfaces are studied in a wide ( ) ( ) range of Knudsen number Kn at low Mach number M with the objectiv e of dev eloping simple, physics-based models. Such flows are encountered in microelectromechanical systems ( ) MEMS , in nanotechnology applications , and in low-pressure env ironments. A new general boundary condition that accoun...

Hypersonic aerothermodynamics for a probe entering a planetary atmosphere is an important issue in space exploration. The probe experiences various Knudsen number regimes, ranging from rarefied to continuum, due to density variation in the planet’s atmosphere. To simulate such multiscale flows, a novel hybrid particle scheme is employed in the present work. The hybrid particle scheme employs th...

Abstract The ability to accurately model condensing flows is crucial for understanding such in many applications. Condensing of pure steam have been studied extensively the past, and several droplet growth models derived. rationale choice condensation humid air less established. Furthermore, only a few validation cases exist. This paper aims identify existing limitations common laws. Hertz—Knud...

Abstract The paper represents an analysis of convective instability in a vertical cylindrical porous microchannel performed using the Galerkin method. dependence critical Rayleigh number on Darcy, Knudsen, and Prandtl numbers, as well ratio thermal conductivities fluid wall, was obtained. It shown that decrease permeability medium (in other words, increase its porosity) causes flow stability. T...

At the microscale, even moderate temperature differences leading to thermal nonequilibrium can result in significant Knudsen forces generated by the energy exchange between gas molecules and solids immersed in a gas. Experimental measurements of the microscale Knudsen force have been reported by Passian et al., Phys. Rev. Lett. 90, 124503 (2003) using heated microcantilevers of atomic force mic...

This paper discusses the provable security of the compression functions introduced by Knudsen and Preneel [?,?,?] that use linear error-correcting codes to build wide-pipe compression functions from underlying blockciphers operating in Davies-Meyer mode. In the information theoretic model, we prove that the Knudsen-Preneel compression function based on an [r, k, d]2e code is collision resistant...

Non-gray phonon transport solvers based on the Boltzmann transport equation (BTE) are frequently employed to simulate sub-micron thermal transport. Typical solution procedures using sequential solution schemes encounter numerical difficulties because of the large spread in scattering rates. For frequency bands with very low Knudsen numbers, strong coupling between the directional BTEs results i...