scholarly journals Numerical Analysis of Flow Phenomena in Discharge Object with Siphon Using Lattice Boltzmann Method and CFD

Mathematics ◽  
2021 ◽  
Vol 9 (15) ◽  
pp. 1734
Author(s):  
Jiří Fürst ◽  
Tomáš Halada ◽  
Milan Sedlář ◽  
Tomáš Krátký ◽  
Pavel Procházka ◽  
...  
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Free Water ◽  
Turbulence Models ◽  
Stationary Flow ◽  
Volume Of Fluid ◽  
Surface Flow ◽  
Flow Structures ◽  
Complex Flow ◽  
Boltzmann Method

This article presents numerical simulation of flow in the discharge object with the welded siphon and the free water level. The main numerical tool used in this study is the lattice Boltzmann method combined with the Volume-of-Fluid approach and the Smagorinski LES model. Some aspects of the numerical method are discussed, especially the formulation of the outlet boundary condition. The simulations are carried out with in-house software based on the open-source Palabos framework. Presented results are compared with the CFD simulations, based on the ANSYS CFX software applying the SST and SAS turbulence models and the free-surface flow modeling by means of the Volume-of-Fluid method. The evolution and interactions of main flow structures are analyzed using visualizations and the spectral analysis. All numerical simulations are verified by the experimental data obtained in the hydraulic laboratory with water circuit. A stationary flow regime has been visualized by means of PIV. Both the vertical planes and horizontal planes have been examined, focused mainly on the regions below and behind the siphon outlet. The results show a good agreement of calculated and measured complex flow structures, including time-averaged and instantaneous flow fields.

scholarly journals Experimental Research and Numerical Analysis of Flow Phenomena in Discharge Object with Siphon

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3330
Author(s):  
Milan Sedlář ◽  
Pavel Procházka ◽  
Martin Komárek ◽  
Václav Uruba ◽  
Vladislav Skála
Keyword(s):  
Experimental Research ◽  
Turbulence Models ◽  
Free Surface Flow ◽  
Stationary Flow ◽  
Surface Flow ◽  
Flow Structures ◽  
Complex Flow ◽  
Flow Topology ◽  
Image Velocimetry ◽  
Flow Phenomena

This article presents results of the experimental research and numerical simulations of the flow in a pumping system’s discharge object with the welded siphon. The laboratory simplified model was used in the study. Two stationary flow regimes characterized by different volume flow rates and water level heights have been chosen. The study concentrates mainly on the regions below and behind the siphon outlet. The mathematical modelling using advanced turbulence models has been performed. The free-surface flow has been carried out by means of the volume-of-fluid method. The experimental results obtained by the particle image velocimetry method have been used for the mathematical model validation. The evolution and interactions of main flow structures are analyzed using visualizations and the spectral analysis. The presented results show a good agreement of the measured and calculated complex flow topology and give a deep insight into the flow structures below and behind the siphon outlet. The presented methodology and results can increase the applicability and reliability of the numerical tools used for the design of the pump and turbine stations and their optimization with respect to the efficiency, lifetime and environmental demands.

Complex Flow Simulation via Lattice Boltzmann Method

2016 ◽  
pp. 38-1-38-30 ◽  
Author(s):  
G Falcucci ◽  
S Melchionna ◽  
S Ubertini ◽  
Sauro Succi
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Flow Simulation ◽  
Complex Flow ◽  
Boltzmann Method

MRT RECTANGULAR LATTICE BOLTZMANN METHOD

2012 ◽  
Vol 23 (05) ◽  
pp. 1250040 ◽  
Author(s):  
JIAN GUO ZHOU
Keyword(s):  
Relaxation Time ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Standard Procedure ◽  
Accurate Solution ◽  
Square Lattice ◽  
Rectangular Lattice ◽  
Complex Flow ◽  
Dominant Feature ◽  
Boltzmann Method

A multiple-relaxation-time (MRT) collision operator is introduced into the author's rectangular lattice Boltzmann method for simulating fluid flows. The model retains both the advantages and the standard procedure of using a constant transformation matrix in the conventional MRT scheme on a square lattice, leading to easy implementation in the algorithm. This allows flow problems characterized by dominant feature in one direction to be solved more efficiently. Two numerical tests have been carried out and shown that the proposed model is able to capture complex flow characteristics and generate an accurate solution if an appropriate lattice ratio is used. The model is found to be more stable compared to the original rectangular lattice Boltzmann method using the single relaxation time.

Very-Large Eddy Simulations of Disk Heat Transfer in a Rotating Cavity Using Lattice-Boltzmann Method

2018 ◽  
Author(s):  
J. Kouwa ◽  
Y. Iso ◽  
F. Polidoro ◽  
S. Gautier
Keyword(s):  
Heat Transfer ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Three Dimensional ◽  
Flow Structures ◽  
Physical Parameters ◽  
Transfer Coefficients ◽  
Experimental Heat ◽  
Large Eddy ◽  
Boltzmann Method

Convective heat transfer in the cavity between two corotating disks is of great importance for turbomachinery applications. The complex three dimensional and unsteady flow structures induced by the Coriolis forces inside the cavity, and therefore the resulting heat transfer, are challenging to be measured in an experiment or predicted by simulation. In this paper a simplified cavity geometry, characterized experimentally by Long at al., has been chosen. The results obtained with a Very Large Eddy Simulation using Lattice-Boltzmann Method for two operating point with different rotation speeds are compared to the experimental heat transfer coefficients at the wall. The simulation results show the characteristic flow structures and behavior induced by the different regimes. A sensitivity analysis of the results is presented, both for numerical parameters such as grid resolution and for physical parameters, namely the throughflow velocity profile and shroud temperature.

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