Topic
Knudsen number
About: Knudsen number is a research topic. Over the lifetime, 5052 publications have been published within this topic receiving 104278 citations.
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01 Jan 1975
TL;DR: In this paper, the unipolar charging rate of small aerosol particles in the transition and free molecule regimes of Knudsen number was derived from a constant collision frequency model of the Boltzmann equation.
Abstract: Calculations are presented of the unipolar charging rate of small aerosol particles in the transition and free molecule regimes of Knudsen number. Numerical results for the charging rate in the transition regime are obtained from a constant collision frequency model of the Boltzmann equation. These results confirm experimental observations that the unipolar charging rates for larger particle charges are only weakly pressure dependent even when the Knudsen number is relatively small. Also, the modification of the near free molecular unipolar charging rate by ion-neutral molecule collisions, is found to depend importantly and in a complex manner on particle size and total particle charge when the image force is included in the ion-particle interaction.
56 citations
01 Jan 2005
56 citations
TL;DR: In this paper, it was shown that as a result of the interaction of part of the molecules with a wall, the viscosity of the Knudsen layer is lower in comparison with the bulk fluid.
Abstract: It was shown that as a result of the interaction of part of the molecules with a wall, the viscosity in the Knudsen layer is lower in comparison with the viscosity in the bulk fluid. The slip condition of Maxwell depends on the normal gradient of the tangential velocity on the wall. The reduction of the viscosity increases the tangential velocity and its normal gradient, and, therefore, increases the slip. The correction factors for the Maxwell expression for one-dimensional plane and tubular isothermal and incompressible flows as a function of the Knudsen number and of the kind of interaction of molecules with the wall were derived.
56 citations
TL;DR: Stokes flow between corrugated plates in microdomains has been analyzed using a perturbation method using the incompressible Navier-Stokes equations, but the velocity-slip is present along the solid-fluid interface.
Abstract: Stokes flow between corrugated plates in microdomains has been analyzed using a perturbation method. This approach used the incompressible Navier-Stokes equations, but the velocity-slip is present along the solid-fluid interface. For the slip flow regime, if we introduce Knudsen number (Kn) herein, 0.01 ≤Kn≤ 0.1, the total flow rate is increasing as a ratio of 1 + 6Knto no-slip Stokes flow. If we consider fixedKncases, the corrugations still decrease the flow rate, consideringO(e2) terms, and the decrease is maximum as the phase shift becomes 180 °.
56 citations
TL;DR: In the present study, different computational improvements were persuaded in order to augment the Fokker-Planck kinetic model, including an accurate time integration scheme, local time stepping and noise reduction, which give rise to very efficient yet accurate solution algorithms.
56 citations