scholarly journals A Numerical Study of Sheet Flow Under Monochromatic Nonbreaking Waves Using a Free Surface Resolving Eulerian Two‐Phase Flow Model

2018 ◽  
Vol 123 (7) ◽  
pp. 4693-4719 ◽  
Author(s):  
Yeulwoo Kim ◽  
Zhen Cheng ◽  
Tian‐Jian Hsu ◽  
Julien Chauchat
Keyword(s):  
Free Surface ◽  
Flow Model ◽  
Two Phase Flow ◽  
Numerical Study ◽  
Phase Flow ◽  
Sheet Flow ◽  
Two Phase

A Two-Phase Flow Model with VOF for Free Surface Flow Problems

2012 ◽  
Vol 232 ◽  
pp. 279-283 ◽  
Author(s):  
Wei Zhang ◽  
You Hong Tang ◽  
Cheng Bi Zhao ◽  
Cheng Zhang
Keyword(s):  
Free Surface ◽  
Flow Model ◽  
Two Phase Flow ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Phase Model ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Problems ◽  
Fluid Sloshing

A numerical model based on the two-phase flow model for incompressible viscous fluid with a complex free surface has been developed in this study. The two-step projection method is employed to solve the Navier–Stokes equations in the numerical solutions, and finite difference method on a staggered grid is used throughout the computation. The two-order accurate volume of fluid (VOF) method is used to track the distorted and broken free surfaces. The two-phase model is first validated by simulating the dam break over a dry bed, in which the numerical results and experimental data agree well. Then 2-D fluid sloshing in a horizontally excited rectangular tank at different excitation frequencies is simulated using this two-phase model. The results of this study show that the two-phase flow model with VOF method is a potential tool for the simulation of nonlinear fluid sloshing. These studies demonstrate the capability of the two-phase model to simulate free surface flow problems with considering air movement effects.

Numerical analysis of a Pelton bucket free surface sheet flow and dynamic performance affected by operating head

2017 ◽  
Vol 231 (3) ◽  
pp. 182-196 ◽  
Author(s):  
Chongji Zeng ◽  
Yexiang Xiao ◽  
Zhengwei Wang ◽  
Jin Zhang ◽  
Yongyao Luo
Keyword(s):  
Free Surface ◽  
Two Phase Flow ◽  
Hydrodynamic Performance ◽  
Phase Flow ◽  
Sheet Flow ◽  
Two Phase ◽  
Pelton Turbine ◽  
Water Head ◽  
Simulation Results ◽  
Surface Sheet

The present paper aims to find out the influence of operating head on the rotating bucket free surface sheet flow and hydrodynamics performance for a Pelton turbine. Three-dimensional unsteady air-water two-phase flow simulations in the rotating buckets were performed by adopting the shear stress transport curvature correction turbulence model and homogenous model. The sensitivities of the unsteady simulation results to moving mesh resolution and computational fluid dynamics solver time-step have been evaluated to discuss the effect of Courant–Friedrichs–Lewy conditions on the two-phase flow simulation. The accuracy of the numerical predicted flow pattern and the hydrodynamic performance results are reasonable when compared with the experimental data. The simulation results indicate that the remaining kinetic energy carried by the outflow under the nondesigned water head is the main reason for the efficiency loss in the Pelton turbine. Under low water head conditions, jet distortion caused by the Coanda effect and flow interference will lead to more severe efficiency deterioration.

scholarly journals A Numerical Study on Oscillatory Flow-Induced Sediment Motion over Vortex Ripples

2015 ◽  
Vol 45 (1) ◽  
pp. 228-246 ◽  
Author(s):  
Xin Chen ◽  
Xiping Yu
Keyword(s):  
Turbulence Model ◽  
Oscillatory Flow ◽  
Flow Model ◽  
Two Phase Flow ◽  
Numerical Study ◽  
Laboratory Data ◽  
Phase Flow ◽  
Mass Force ◽  
Two Phase ◽  
Reference Concentration

AbstractA two-dimensional, two-phase flow model is applied to the study of sediment motion over vortex ripples under oscillatory flow conditions. The Reynolds-averaged continuity equations and momentum equations for both the fluid and sediment phases, which include the drag force, the added mass force, the lift force for interphase coupling, and the standard k–ε turbulence model as well as the Henze–Tchen particle turbulence model for closure, are numerically solved with a finite-volume method. The model is effective over the whole depth from the undisturbed sandy bed to the low concentration region above the ripples. Neither a reference concentration nor a pickup function is required over the ripple bed as in a conventional advection–diffusion model. There is also no need to identify the bed load and the suspended load. The study focuses on the effects of erodible ripples on the intrawave flow and sediment motion over the ripples. The computational results show reasonable agreement with the available laboratory data. It is demonstrated that the formation–ejection process of vortices and the trapping–lifting process of sediment over vortex ripples can be well described by the two-phase flow model. The numerical model can also accurately predict the vertical distribution of the mean sediment concentration.

scholarly journals Application of a Eulerian two-phase flow model to scour processes

2018 ◽  
Vol 40 ◽  
pp. 05015 ◽  
Author(s):  
Antoine Mathieu ◽  
Tim Nagel ◽  
Cyrille Bonamy ◽  
Julien Chauchat ◽  
Zhen Cheng ◽  
...  
Keyword(s):  
Experimental Data ◽  
Vortex Shedding ◽  
Flow Model ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Submarine Pipeline ◽  
Sheet Flow ◽  
Two Phase ◽  
One Dimensional ◽  
Quantitative Results

In this paper, the application of a two-phase flow model to scour processes is presented. The model is first calibrated against experimental data of unidirectional sheet-flow (one-dimensional configuration). The model is then applied to multi-dimensional configurations for the scour under a submarine pipeline and around a vertical pile. The results show that quantitative results can be obtained at the upstream sides of structures, the lee-wake erosion driven by the vortex shedding deserves further research.

A two-phase flow model of wave-induced sheet flow

2003 ◽  
Vol 41 (3) ◽  
pp. 299-310 ◽  
Author(s):  
Tai-WeN. Hsu ◽  
Hsien-Kuo Chang ◽  
Chih-MiN. Hsieh
Keyword(s):  
Flow Model ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Sheet Flow ◽  
Two Phase ◽  
Wave Induced
Sign in / Sign up

Export Citation Format

Share Document