scholarly journals A new method for predicting transport properties of polar firn with respect to gases on the pore-space scale

2002 ◽  
Vol 35 ◽  
pp. 538-544 ◽  
Author(s):  
Johannes Freitag ◽  
Uwe Dobrindt ◽  
Josef Kipfstuhl
Keyword(s):  
Lattice Boltzmann ◽  
Diffusion Coefficients ◽  
Pore Space ◽  
Effective Diffusion ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Diffusive Transport ◽  
Navier Stokes Equation ◽  
The North ◽  
Effective Diffusion Coefficients

AbstractIn this study a powerful tool to investigate the permeabilities and effective diffusion coefficients of polar firn is presented using a combination of an experimental method for three-dimensional pore-structure reconstruction and two models to simulate advective and diffusive transports of gases through the pore space. the reconstruction follows a semi-automated digital analysis of serial surface sections. the simulations are based on a three-dimensional lattice Boltzmann formulation. They separately solve the Navier–Stokes equation and the diffusive transport equations. In a first application, effective diffusion coefficients and permeabilities are calculated from firn samples of a core drilled during the North Greenland Traverse 1993–95. the estimated relationships of diffusivity and permeability to the open porosity are expressed by power-law functions with exponents 2.1 and 3.4, respectively.

scholarly journals A lattice-Boltzmann scheme of the Navier–Stokes equation on a three-dimensional cuboid lattice

2019 ◽  
Vol 78 (4) ◽  
pp. 1053-1075 ◽  
Author(s):  
Lian-Ping Wang ◽  
Haoda Min ◽  
Cheng Peng ◽  
Nicholas Geneva ◽  
Zhaoli Guo
Keyword(s):  
Stokes Equation ◽  
Lattice Boltzmann ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Lattice Boltzmann Scheme

scholarly journals ESTIMATION OF THE SIZE OF STAGNATION ZONES ON THE TERRITORY OF THE PROPANE-BUTANE TANK FARM AIMED AT INCREASING THE SAFETY OF THE FACILITY

2019 ◽  
Vol 16 (32) ◽  
pp. 656-667
Author(s):  
Mikhail V. OMELCHUK ◽  
Yuliya S. KOROTKOVA ◽  
Elizaveta A. VORONTSOVA
Keyword(s):  
Three Dimensional ◽  
Navier Stokes ◽  
Design Stage ◽  
Three Dimensional Model ◽  
Gas Dynamics Equations ◽  
Navier Stokes Equation ◽  
Three Dimensional Modeling ◽  
The North ◽  
Tank Farm ◽  
Propane Butane

The safety of the territory is directly dependent upon the propane-butane storage and use technology. The paper reveals the efficiency of FlowVision software-based computational fluid dynamics technology (CFD) in modeling the stagnation zones and the behavior of fuel-air mixture (FAM) cloud within the territory of storage facilities. Propane-butane storage tank farm storage was selected as the object of research. CAD SolidWorks was used in the design of his three-dimensional model. Methods using "dispersed heavy gas models" have been developed. It is based on the numerical solution of three-dimensional fluid and gas dynamics equations, including the laws of conservation of mass, momentum (the Navier-Stokes equation) and constitutive equation. Recommendations on changes to be implemented during the design stage of tank farms with propane-butane mixture have been developed in order to increase facility safety in case of equipment depressurization. It is known that buildings, located on the territory, impair the airflow, resulting in the presence of large stagnant zones. It has been established that as a result of the movement of air flow through the territory of the tank farm, the maximum areas of stagnation zones are observed with the north wind and the minimum – with the southeast wind. Using the three-dimensional modeling techniques and finite volumes the stagnation zones in the tank farm were computed for different wind directions and measurement heights, enabling a comprehensive assessment of the situation at the facility in question and development of series of safety-increasing measures.

Lattice-Boltzmann Simulation of Two-Phase Fluid Flows

1998 ◽  
Vol 09 (08) ◽  
pp. 1383-1391 ◽  
Author(s):  
Yu Chen ◽  
Shulong Teng ◽  
Takauki Shukuwa ◽  
Hirotada Ohashi
Keyword(s):  
Lattice Boltzmann ◽  
Fluid Flows ◽  
Navier Stokes ◽  
Interface Model ◽  
Two Phase ◽  
Navier Stokes Equation ◽  
Lattice Boltzmann Simulation ◽  
Dam Breaking ◽  
Volumetric Stress ◽  
Phase Fluid

A model with a volumetric stress tensor added to the Navier–Stokes Equation is used to study two-phase fluid flows. The implementation of such an interface model into the lattice-Boltzmann equation is derived from the continuous Boltzmann BGK equation with an external force term, by using the discrete coordinate method. Numerical simulations are carried out for phase separation and "dam breaking" phenomena.

Numerical Simulation of High Reynolds Number Flow Structure in a Lid-Driven Cavity Using MRT-LES

2014 ◽  
Vol 554 ◽  
pp. 665-669
Author(s):  
Leila Jahanshaloo ◽  
Nor Azwadi Che Sidik
Keyword(s):  
Reynolds Number ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Numerical Technique ◽  
Lattice Boltzmann Model ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Driven Cavity ◽  
Reynolds Number Flow ◽  
Boltzmann Method

The Lattice Boltzmann Method (LBM) is a potent numerical technique based on kinetic theory, which has been effectively employed in various complicated physical, chemical and fluid mechanics problems. In this paper multi-relaxation lattice Boltzmann model (MRT) coupled with a Large Eddy Simulation (LES) and the equation are applied for driven cavity flow at different Reynolds number (1000-10000) and the results are compared with the previous published papers which solve the Navier stokes equation directly. The comparisons between the simulated results show that the lattice Boltzmann method has the capacity to solve the complex flows with reasonable accuracy and reliability. Keywords: Two-dimensional flows, Lattice Boltzmann method, Turbulent flow, MRT, LES.

Cylinder rolling on a wall at low Reynolds numbers

2011 ◽  
Vol 685 ◽  
pp. 461-494 ◽  
Author(s):  
Alain Merlen ◽  
Christophe Frankiewicz
Keyword(s):  
Three Dimensional ◽  
Reynolds Numbers ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Flow Around A Cylinder ◽  
Low Reynolds Numbers ◽  
Initial Location ◽  
Upstream Pressure ◽  
Small Reynolds Numbers ◽  
Onset Of Cavitation

AbstractThe flow around a cylinder rolling or sliding on a wall was investigated analytically and numerically for small Reynolds numbers, where the flow is known to be two-dimensional and steady. Both prograde and retrograde rotation were analytically solved, in the Stokes regime, giving the values of forces and torque and a complete description of the flow. However, solving Navier–Stokes equation, a rotation of the cylinder near the wall necessarily induces a cavitation bubble in the nip if the fluid is a liquid, or compressible effects, if it is a gas. Therefore, an infinite lift force is generated, disconnecting the cylinder from the wall. The flow inside this interstice was then solved under the lubrication assumptions and fully described for a completely flooded interstice. Numerical results extend the analysis to higher Reynolds number. Finally, the effect of the upstream pressure on the onset of cavitation is studied, giving the initial location of the phenomenon and the relation between the upstream pressure and the flow rate in the interstice. It is shown that the flow in the interstice must become three-dimensional when cavitation takes place.

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