scholarly journals A slip model for rarefied gas flows at arbitrary Knudsen number

2008 ◽  
Vol 93 (25) ◽  
pp. 253103 ◽  
Author(s):  
Lin Wu
Keyword(s):  
Knudsen Number ◽  
Rarefied Gas ◽  
Gas Flows ◽  
Slip Model ◽  
Rarefied Gas Flows

Flow and thermal field investigation of rarefied gas in a trapezoidal micro/nano-cavity using DSMC

2021 ◽  
pp. 2150162
Author(s):  
Mostafa Zakeri ◽  
Ehsan Roohi
Keyword(s):  
Knudsen Number ◽  
Thermal Field ◽  
Rarefied Gas ◽  
Direct Simulation Monte Carlo ◽  
Field Investigation ◽  
Gas Flows ◽  
Fourier Law ◽  
Rarefied Gas Flows ◽  
Knudsen Numbers ◽  
Simulation Monte Carlo

The impetus of the this study is to investigate flow and thermal field in rarefied gas flows inside a trapezoidal micro/nano-cavity using the direct simulation Monte Carlo (DSMC) technique. The investigation covers the hydrodynamic properties and thermal behavior of the flow. The selected Knudsen numbers for this study are arranged in the slip and transition regimes. The results show the center of the vortex location moves by variation in the Knudsen numbers. Also, as the Knudsen number increases, the non-dimensional shear stress increases, but the distribution deviates from a symmetrical profile. The cold to hot transfer, which is in contrast with the conventional Fourier law, is observed. We show that the heat transfer is affected by the second derivative of the velocity. By increasing the Knudsen number, the transferred heat through the walls decreases, but the contraction/expansion effects on the temperature in the corner of the cavity become higher.

Shock polar investigation in supersonic rarefied gas flows over a circular cylinder

2021 ◽  
Vol 33 (5) ◽  
pp. 052006
Author(s):  
Hassan Akhlaghi ◽  
Ehsan Roohi ◽  
Abbas Daliri ◽  
Mohammad-Reza Soltani
Keyword(s):  
Circular Cylinder ◽  
Rarefied Gas ◽  
Gas Flows ◽  
Rarefied Gas Flows

scholarly journals Rarefied gas flows through meshes and implications for atmospheric measurements

2001 ◽  
Vol 19 (5) ◽  
pp. 563-569 ◽  
Author(s):  
J. Gumbel
Keyword(s):  
Middle Atmosphere ◽  
Rarefied Gas ◽  
Direct Simulation Monte Carlo ◽  
Atmospheric Composition ◽  
Gas Flows ◽  
Atmospheric Measurements ◽  
Rarefied Gas Flows ◽  
Flow Disturbances ◽  
Composition And Structure ◽  
Compression Effects

Abstract. Meshes are commonly used as part of instruments for in situ atmospheric measurements. This study analyses the aerodynamic effect of meshes by means of wind tunnel experiments and numerical simulations. Based on the Direct Simulation Monte Carlo method, a simple mesh parameterisation is described and applied to a number of representative flow conditions. For open meshes freely exposed to the flow, substantial compression effects are found both upstream and downstream of the mesh. Meshes attached to close instrument structures, on the other hand, cause only minor flow disturbances. In an accompanying paper, the approach developed here is applied to the quantitative analysis of rocket-borne density measurements in the middle atmosphere.Key words. Atmospheric composition and structure (instruments and techniques; middle atmosphere – composition and chemistry)

scholarly journals An open source, parallel DSMC code for rarefied gas flows in arbitrary geometries

2010 ◽  
Vol 39 (10) ◽  
pp. 2078-2089 ◽  
Author(s):  
T.J. Scanlon ◽  
E. Roohi ◽  
C. White ◽  
M. Darbandi ◽  
J.M. Reese
Keyword(s):  
Open Source ◽  
Rarefied Gas ◽  
Gas Flows ◽  
Rarefied Gas Flows ◽  
Arbitrary Geometries
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