Free Surface Model Derived From the Analytical Solution of Stokes Flow in a Wedge

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
R. W. Hewson
Keyword(s):  
Free Surface ◽  
Stokes Flow ◽  
Thin Liquid Film ◽  
Industrial Process ◽  
Surface Model ◽  
Coating Flows ◽  
Element Simulation ◽  
Extraction Processes ◽  
Full Solution ◽  
Free Surface Model

The formation of a thin liquid film onto a moving substrate is a commonly encountered industrial process, and one that is encountered in lubrication, oil extraction processes, and coating flows. The formation of such a film is analyzed via the analytical Stokes flow solution for the flow in a wedge bounded on one side by a free surface and on the other by a moving surface. The full solution is obtained by numerically integrating a set of ordinary differential equations from far downstream, in the region of the final film thickness. The results show excellent agreement with the results obtained by the Bretherton equation, the Ruschak equation, the Coyne and Elrod model, and a two-dimensional free surface finite element simulation of the problem.

Analyze of the Size of Secondary Droplets due to Film Separation at the Blade Trailing Edge

2014 ◽  
Author(s):  
Hans Josef Dohmen ◽  
Friedrich-Karl Benra ◽  
Cornelius Schepers ◽  
Sebastian Schuster
Keyword(s):  
Free Surface ◽  
Liquid Film ◽  
Thin Liquid Film ◽  
Third Party ◽  
Working Fluid ◽  
Surface Model ◽  
Trailing Edge ◽  
Secondary Droplets ◽  
Free Surface Model ◽  
Film Separation

In many turbo machinery applications the working fluid is a mixture of a gas and a liquid. In such two-phase flows the liquid phase can be assumed to be a dispersed droplet flow. As the fluid passes the blades, a part of the droplets is deposited on the blades and forms a thin liquid film. At the trailing edge the thin liquid film separates and forms secondary droplets. In this paper the ability of numerical investigations to study the size of secondary droplets is analyzed. In a first step a program solving the Thin Film Equations is used to analyze the film flow on the inlet guide vanes of an axial compressor. Secondly a CFD study with a Free Surface Model is performed to analyze the film stripping process. The ability of the Free Surface model to investigate film separation is validated against third party experimental results and the pro and contras of the Free-Surface model are presented. In the last step the stability of the formed droplets is investigated and the final droplet size is calculated.

An Improved Single-Phase Free-Surface Lattice Boltzmann Model with Surface Tension and Wall Adhesion

2013 ◽  
Vol 300-301 ◽  
pp. 1062-1066
Author(s):  
Yang Yu ◽  
Li Chen ◽  
Jian Hua Lu ◽  
Guo Xiang Hou
Keyword(s):  
Surface Tension ◽  
Free Surface ◽  
Lattice Boltzmann ◽  
Single Phase ◽  
Lattice Boltzmann Model ◽  
Surface Model ◽  
Two Phase ◽  
Surface Method ◽  
Free Surface Model ◽  
Boltzmann Model

Free-surface model with surface tension and wall adhesion(wetting) is a very efficient technique to simulate two-phase flows with high density and viscosity ratios, such as etching and casting processes. In this paper, a conservative surface tension and wall adhesion model based on lattice Boltzmann single-phase free-surface method is proposed. The effectiveness of the model is demonstrated by simulating the flows induced by wall adhesion and surface tension, and filling processes in a 2D cavity.

A Free-Surface Model of a Jet Impinging On a Sprinkler Head

2014 ◽  
Vol 11 ◽  
pp. 1184-1195 ◽  
Author(s):  
T. Myers ◽  
A. Marshall ◽  
H. Baum
Keyword(s):  
Free Surface ◽  
Surface Model ◽  
Free Surface Model ◽  
Sprinkler Head

A lattice-Boltzmann free surface model for injection moulding of a non-Newtonian fluid

2020 ◽  
Vol 378 (2175) ◽  
pp. 20190407 ◽  
Author(s):  
Daniele Chiappini
Keyword(s):  
Free Surface ◽  
Lattice Boltzmann ◽  
Injection Moulding ◽  
Soft Matter ◽  
Density Ratio ◽  
Acrylonitrile Butadiene Styrene ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Surface Model ◽  
Free Surface Model

The aim of this work is to present a lattice Boltzmann (LB) model devoted to dealing with non-Newtonian free surface flow. The combination of LB solver with a free-surface model allows dealing with multiphase flows where the density ratio in between the two considered phases is so high that the lighter phase can be neglected. For this particular set of multiphase models, the interface between the two phases is numerically reconstructed and transported via a diffusion equation. Moreover, the application of a Carreau approach for viscosity modelling allows the introduction of effects related to shear stress on fluid flow evolution. Two different non-Newtonian silicon-like materials have been considered here, namely the polystyrene and acrylonitrile butadiene styrene. Here, the author, after the mandatory model validation with a reference configuration, presents some applications of injection moulding for two different test-cases: the former is the injection in a labyrinth-like gasket, whereas the latter is the injection in a porous media. This article is part of the theme issue ‘Fluid dynamics, soft matter and complex systems: recent results and new methods’.

scholarly journals Fluid Structure Interaction of 2D Objects through a Coupled KBC-Free Surface Model

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1212
Author(s):  
Daniele Chiappini
Keyword(s):  
Free Surface ◽  
Lattice Boltzmann ◽  
Numerical Data ◽  
Lattice Boltzmann Model ◽  
Surface Model ◽  
Water Tank ◽  
Structure Interaction ◽  
Calm Water ◽  
Free Surface Model ◽  
Boltzmann Model

In this study, the capabilities of a coupled KBC-free surface model to deal with fluid solid interactions with the slamming of rigid obstacles in a calm water tank were analyzed. The results were firstly validated with experimental and numerical data available in literature and, thereafter, some additional analyses was carried out to understand the main parameters’ influence on slamming coefficient. The effect of grid resolution and Reynolds number were firstly considered to choose the proper grid and to present the weak impact of such a non-dimensional number on process evolution. Hence, the influence of Froude number on fluid-dynamics quantities was pointed out considering vertical impacts of both cylindrical, as in the references, and ellipsoidal obstacles. Different formulations of slamming coefficient were used and compared. Results are pretty encouraging and they confirm the effectiveness of lattice Boltzmann model to deal with such a problem. This leaves the door open to additional improvements addressed to the study of free buoyant bodies immersed in a fluid domain.

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