scispace - formally typeset
Search or ask a question
Topic

Rarefaction

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


Papers
More filters
Journal ArticleDOI
TL;DR: In this paper, the authors considered the oscillatory flow of an incom- pressible Newtonian gas through a circular nanotube, with first order wall slip due to rarefaction.
Abstract: Gas flow through nanoscale conduits shows distinctly different physics compared to flow at the macroscale. One of the first manifestations of this is the appearance of wall slip. Here we consider the oscillatory flow of an incom- pressible Newtonian gas through a circular nanotube, with first order wall slip due to rarefaction. It was found that the ma- jor effect of wall slip at lower oscillation frequencies is to alter the instantaneous velocity profiles from Poiseuille-like to more plug-like, with an overall enhancement to the fluid velocity magnitude. However, at higher frequencies the en- hancement to velocity magnitude due to wall slip is greatly diminished, and rarefaction introduces a region of backflow near the centerline of the nanotube. These flow characteristics may have important implications for the design of various practical applications of unsteady gas flow through nanoscale conduits, from fuel cell membranes to gas-powered nanomachines constructed from carbon nanotubes.

11 citations

Journal ArticleDOI
TL;DR: In this article, an exact analytic solution of the problem of determining the intensities of the waves leading to extreme values of the gasdynamic variables (static pressure, temperature, etc.) behind the wave is found using Lagrangian multipliers.
Abstract: A “shock and subsequent rarefaction wave” shock-wave system in a plane supersonic inviscid non-heat-conducting gas flow is considered. An exact analytic solution of the problem of determining the intensities of the waves leading to extreme values of the gasdynamic variables (static pressure, temperature, etc.) behind the wave is found using Lagrangian multipliers. These systems are related to the optimal ones [1, 2]. The parameters of the problem are the free-stream Mach number, the specific heat ratio, and the total flow turning angle in the wave system. Analytic solutions determining the boundaries of monotonic and nonmonotonic behavior of the gasdynamic variables behind the system are presented. The effect of the specific heat ratio on the dimensions of the domains of existence of the optimal waves is investigated.

11 citations

Journal ArticleDOI
TL;DR: In this paper, the role of collisional coupling between a proton-electron charge-neutral fluid and a neutral hydrogen fluid for the 1D Riemann problem initiated in a constant pressure and density background state by a discontinuity in the magnetic field was investigated.
Abstract: The role of slow-mode MHD shocks in magnetic reconnection is one of great importance for energy conversion and transport, but in many astrophysical plasmas the plasma is not fully ionised. In this paper, we investigate, using numerical simulations, the role of collisional coupling between a proton-electron charge-neutral fluid and a neutral hydrogen fluid for the 1D Riemann problem initiated in a constant pressure and density background state by a discontinuity in the magnetic field. This system, in the MHD limit, is characterised by two waves: a fast-mode rarefaction wave that drives a flow towards a slow-mode MHD shock. The system evolves through four stage: initiation, weak coupling, intermediate coupling and a quasi steady state. The initial stages are characterised by an over-pressured neutral region that expands with characteristics of a blast wave. In the later stages, the system tends towards a self-similar solution where the main drift velocity is concentrated in the thin region of the shock front. Due to the nature of the system, the neutral fluid is overpressured by the shock when compared to a purely hydrodynamic shock which results in the neutral fluid expanding to form the shock precursor. The thickness of the shockfront once it has formed proportional to the ionisation fraction to the power -1.2, which is a smaller exponent than would be naively expected from simple scaling arguments. One interesting result is that the shock front is a continuous transition of the physical variables for sub-sonic velocity upstream of the shock front (a c-shock) to a sharp jump in the physical variables followed by a relaxation to the downstream values for supersonic upstream velocity (a j-shock). The frictional heating that results from the velocity drift across the shock front can amount to approximately two per cent of the reference magnetic energy.

11 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated the fluidized granular materials (FGM) with the van der Waals normal form (VDWF) under the effects of friction and viscosity.
Abstract: This paper investigates the fluidized granular materials (FGM) with the van der Waals normal form (VDWF) under the effects of friction and viscosity. The system of macroscopic balance is presented, including the mass, momentum, and energy equations of local densities. For two different types of collisions, elastic and inelastic collisions, analytical solutions of the nonlinear PDEs governing the granular model are investigated using the hydrodynamic equations for granular matter motion. The integrability of the proposed model is analyzed by applying the Painleve analysis. Moreover, the Backlund transformation (BT) is established using the Painleve truncation expansion. New traveling wave solutions of the VDWF within FGM are obtained by using the BT, tanh function, Jacobi elliptic function methods to study the phase separation phenomenon. As two pairs of rarefaction and shock waves emerge and travel away giving the appearance of bubbles, the resulting solutions of the proposed model show a behavior similar to those found in the molecular dynamic simulations. The dispersion relation and their properties to the model equation are investigated. Besides, stability analysis of the VDWF in its ODE form is demonstrated using the phase portrait classifications. Finally, using two- and three-dimensional graphics for seeking model solutions under the influence of friction and viscosity, qualitative agreements with previous related works are shown.

11 citations

Journal ArticleDOI
TL;DR: In this article, the binary nucleation theory is extended to include vapor phase association and two opposite influences due to stable association complexes have been derived, a kinetic one increases the nucleation rate and a larger, thermodynamic effect acts contradictory.
Abstract: The binary nucleation theory is extended to include vapor phase association. Similar to the effects found for pure vapors, two opposite influences due to stable association complexes have been derived. A kinetic one increases the nucleation rate and a larger, thermodynamic effect acts contradictory. The developed theory is applied to the water–acetic acid system. Extensive experiments were performed in the unsteady rarefaction wave of a preheated shock tube. The variation of the measured critical supersaturation as a function of mixture composition was found to agree well with the predictions of the theory.

11 citations


Network Information
Related Topics (5)
Turbulence
112.1K papers, 2.7M citations
79% related
Boundary layer
64.9K papers, 1.4M citations
78% related
Reynolds number
68.4K papers, 1.6M citations
78% related
Partial differential equation
70.8K papers, 1.6M citations
75% related
Boundary value problem
145.3K papers, 2.7M citations
75% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20224
2021105
202064
201964
201864
201773