scholarly journals Lattice Boltzmann Simulations in the Slip and Transition Flow Regime with the Peano Framework

2012 ◽  
Vol 02 (03) ◽  
pp. 101-110 ◽  
Author(s):  
Philipp Neumann ◽  
Till Rohrmann
Keyword(s):  
Flow Regime ◽  
Lattice Boltzmann ◽  
Transition Flow ◽  
Transition Flow Regime ◽  
Lattice Boltzmann Simulations

scholarly journals Numerical Modelling of Microchannel Gas Flows in the Transition Flow Regime Using the Cascaded Lattice Boltzmann Method

Entropy ◽  
2019 ◽  
Vol 22 (1) ◽  
pp. 41
Author(s):  
Qing Liu ◽  
Xiang-Bo Feng
Keyword(s):  
Flow Regime ◽  
Lattice Boltzmann ◽  
Effective Viscosity ◽  
Gas Flow ◽  
Specular Reflection ◽  
Collision Operator ◽  
Slip Boundary Condition ◽  
Gas Flows ◽  
Transition Flow ◽  
Transition Flow Regime

In this article, a lattice Boltzmann (LB) method for studying microchannel gas flows is developed in the framework of the cascaded collision operator. In the cascaded lattice Boltzmann (CLB) method, the Bosanquet-type effective viscosity is employed to capture the rarefaction effects, and the combined bounce-back/specular-reflection scheme together with the modified second-order slip boundary condition is adopted so as to match the Bosanquet-type effective viscosity. Numerical simulations of microchannel gas flow with periodic and pressure boundary conditions in the transition flow regime are carried out to validate the CLB method. The predicted results agree well with the analytical, numerical, and experimental data reported in the literature.

scholarly journals A Comparison and Unification of Ellipsoidal Statistical and Shakhov BGK Models

2015 ◽  
Vol 7 (2) ◽  
pp. 245-266 ◽  
Author(s):  
Songze Chen ◽  
Kun Xu ◽  
Qingdong Cai
Keyword(s):  
Kinetic Model ◽  
Flow Regime ◽  
Free Parameter ◽  
Numerical Solutions ◽  
Test Cases ◽  
Transition Flow ◽  
New Model ◽  
Transition Flow Regime ◽  
Generalized Kinetic Model ◽  
S Model

AbstractThe Ellipsoidal Statistical model (ES-model) and the Shakhov model (Smodel) were constructed to correct the Prandtl number of the original BGK model through the modification of stress and heat flux. With the introduction of a new parameter to combine the ES-model and S-model, a generalized kinetic model can be developed. This new model can give the correct Navier-Stokes equations in the continuum flow regime. Through the adjustment of the new parameter, it provides abundant dynamic effect beyond the ES-model and S-model. Changing the free parameter, the physical performance of the new model has been tested numerically. The unified gas kinetic scheme (UGKS) is employed for the study of the new model. In transition flow regime, many physical problems, i.e., the shock structure and micro-flows, have been studied using the generalized model. With a careful choice of the free parameter, good results can be achieved for most test cases. Due to the property of the Boltzmann collision integral, the new parameter in the generalized kinetic model cannot be fully determined. It depends on the specific problem. Generally speaking, the Smodel predicts more accurate numerical solutions in most test cases presented in this paper than the ES-model, while ES-model performs better in the cases where the flow is mostly driven by temperature gradient, such as a channel flow with large boundary temperature variation at high Knudsen number.

Fibrous Filter Efficiency and Pressure Drop in the Viscous-Inertial Transition Flow Regime

2012 ◽  
Vol 46 (2) ◽  
pp. 138-147 ◽  
Author(s):  
J. A. Hubbard ◽  
J. E. Brockmann ◽  
J. Dellinger ◽  
D. A. Lucero ◽  
A. L. Sanchez ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Flow Regime ◽  
Transition Flow ◽  
Fibrous Filter ◽  
Filter Efficiency ◽  
Transition Flow Regime
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