scholarly journals Cylindrical Couette flow of a rarefied gas: Effect of a boundary condition on the inverted velocity profile

2015 ◽  
Vol 92 (1) ◽  
Author(s):  
Shingo Kosuge
2003 ◽  
Vol 68 (1) ◽  
Author(s):  
Kazuo Aoki ◽  
Hiroaki Yoshida ◽  
Toshiyuki Nakanishi ◽  
Alejandro L. Garcia

Author(s):  
Yuan Hu ◽  
Quanhua Sun ◽  
Jing Fan

Gas flow over a micro cylinder is simulated using both a compressible Navier-Stokes solver and a hybrid continuum/particle approach. The micro cylinder flow has low Reynolds number because of the small length scale and the low speed, which also indicates that the rarefied gas effect exists in the flow. A cylinder having a diameter of 20 microns is simulated under several flow conditions where the Reynolds number ranges from 2 to 50 and the Mach number varies from 0.1 to 0.8. It is found that the low Reynolds number flow can be compressible even when the Mach number is less than 0.3, and the drag coefficient of the cylinder increases when the Reynolds number decreases. The compressible effect will increase the pressure drag coefficient although the friction coefficient remains nearly unchanged. The rarefied gas effect will reduce both the friction and pressure drag coefficients, and the vortex in the flow may be shrunk or even disappear.


2002 ◽  
Vol 12 (03) ◽  
pp. 445-459 ◽  
Author(s):  
LILIANA M. GRAMANI CUMIN ◽  
GILBERTO M. KREMER ◽  
FELIX SHARIPOV

The solution of the field equations of the cylindrical Couette flow problem for a rarefied gas is found when the state of equilibrium between the cylinders is perturbed by the following small thermodynamic forces: (i) a pressure difference; (ii) an angular velocity difference; and (iii) a temperature difference. The flow is analyzed within the framework of continuum mechanics by using the field equations that follow from the balance equations of mass, momentum and energy of a viscous and heat conducting gas. These equations are solved analytically by considering slip and jump boundary conditions. The fields of density, velocity, temperature, heat flux vector and viscous stress tensor are calculated as functions of the Knudsen number and of the angular velocity of the rotating cylinders for each thermodynamic force. The asymptotic behaviors of these fields are compared with those obtained from a kinetic model of the Boltzmann equation. The influence of the slip and jump boundary conditions on the solutions is also discussed.


1967 ◽  
Vol 10 (6) ◽  
pp. 1200 ◽  
Author(s):  
Carlo Cercignani

1991 ◽  
Vol 69 (12) ◽  
pp. 1429-1440
Author(s):  
M. A. Mahmoud ◽  
G. A. Shalaby

A kinetic-theory treatment of the cylindrical Couette flow is considered. A generalization of the case of a surface with an arbitrary reflection coefficient that depends on the nature of the surface. In this paper we consider that the reflection coefficients of the inner and outer walls are different. A model kinetic equation of the BGK (Bhatnger–Gross–Krook) type is solved using the method of moments with a two-sided distribution function. The dependence of the velocity and shear stress on the reflection coefficient is obtained.


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