Rarefaction

About: Rarefaction is a research topic. Over the lifetime, 1852 publications have been published within this topic receiving 26943 citations.

On the frame dependence of constitutive equations. I. Heat transfer through a rarefied gas between two rotating cylinders

Abstract: To verify the principle of material frame indifference a numerical calculation of the heat flux field in a rotating gas has been carried out based on the kinetic equation over wide ranges of gas rarefaction and angular velocity It has been confirmed that a radial gradient of the temperature causes a tangential heat flux Also, it has been found that the radial heat flux is affected by the rotation

Interaction of rarefaction waves with area reductions in ducts

Abstract: The interaction of a rarefaction wave with a gradual monotonic area reduction of finite length in a duct, which produces transmitted and reflected rarefaction waves and other possible rarefaction and shock waves, was studied both analytically and numerically. A quasi-steady flow analysis which is analytical for an inviscid flow of a perfect gas was used first to determine the domains of and boundaries between four different wave patterns that occur at late times, after all local transient disturbances from the interaction process have subsided. These boundaries and the final constant strengths of the transmitted, reflected and other waves are shown as a function of both the incident rarefaction-wave strength and area-reduction ratio, for the case of diatomic gases and air with a specific-heat ratio of 7/5. The random-choice method was then used to solve numerically the conservation equations governing the one-dimensional non-stationary gas flow for many different combinations of rarefaction-wave strengths and area-reduction ratios. These numerical results show clearly how the transmitted, reflected and other waves develop and evolve with time, until they eventually attain constant strengths, in agreement with quasi-steady flow predictions for the asymptotic wave patterns. Note that in all of this work the gas in the area reduction is initially at rest.

Propagation and oblique collision of electrostatic solitary waves in quantum pair-plasmas

Abstract: Oblique interaction of small but finite-amplitude Korteweg de-Vries-type electrostatic solitary structures is investigated in an unmagnetized three-component pair-plasma in the framework of quantum hydrodynamics model using the extended Poincare–Lighthill–Kuo perturbation method and collision phase-shift was evaluated for different plasma parameters, such as fractional concentration of plasma constituents, quantum diffraction parameter, and collision angle. Based on numerical analysis, it is found that small changes in these parameters significantly affects the collision phase-shifts of interacting solitons. It is also observed that for a given fractional pair-density, a critical value for quantum diffraction parameter separates regions in which propagations of only compression or rarefaction solitary excitations exist. Numerical analysis also reveals that the collision phase-shifts in trajectories of solitons change the sign depending on the critical plasma values Hcr and θcr.