Using the Multilayer Free-Surface Flow Model to Solve Wave Problems

2017 ◽  
Vol 50 (5) ◽  
pp. 459-465
Author(s):  
V. A. Prokof’ev
Keyword(s):  
Free Surface ◽  
Flow Model ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Wave Problems

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.

scholarly journals WAVE MOTION NEAR A BREAKWATER ROUNDHEAD

2012 ◽  
Vol 1 (33) ◽  
pp. 71
Author(s):  
Takahide Honda ◽  
Peter Wellens ◽  
Marcel Van Gent
Keyword(s):  
Free Surface ◽  
Wave Motion ◽  
Flow Model ◽  
Stokes Equations ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Flow Solver ◽  
Physical Model Tests

COMFLOW is a general 3D free-surface flow solver. The numerical method is based on the Navier-Stokes equations in a porous medium, with additional force terms to represent the (turbulent) interaction of the flow with the medium. The free surface is displaced by means of the Volume-Of-Fluid method. The main objective in this paper is to validate the permeable flow model in 3D. Tailor-made physical model tests were performed for this purpose. In the experiment surface elevations are measured inside and around a permeable structure with 18 wave gauges in total. The measurements are represented well by the simulation results.

scholarly journals 3D SIMULATION OF WAVE INTERACTION WITH PERMEABLE STRUCTURES

2011 ◽  
Vol 1 (32) ◽  
pp. 28 ◽  
Author(s):  
Peter Wellens ◽  
M.J.A. Borsboom ◽  
M.R.A. Van Gent
Keyword(s):  
Free Surface ◽  
Reflection Coefficient ◽  
Flow Model ◽  
Wave Interaction ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Navier Stokes ◽  
Flow Solver ◽  
Simulation Results ◽  
Rubble Mound Breakwaters

COMFLOW is a general 3D free-surface flow solver. The main objective in this paper is to extend the solver with a permeable flow model to simulate wave interaction with rubble-mound breakwaters. The extended Navier-Stokes equations for permeable flow are presented and we show the discretization of these equations as they are implemented in COMFLOW. An analytical solution for the reflection coefficient of a permeable structure is derived and the numerical model is compared to the solution. In addition, a validation study has been performed, in which we compare the numerical results with an experiment. In the experiment, pressures and surface elevations are measured inside a permeable structure. The measurements are represented well by the simulation results. At the end, a 3D application of the model is shown.

Improvement on Simulation Methods of Fluid Transient Processes in Turbine Tailrace Tunnel

2020 ◽  
Author(s):  
Boran Zhang ◽  
Wuyi Wan ◽  
Li Bi
Keyword(s):  
Free Surface ◽  
Flow Condition ◽  
Flow Model ◽  
Draft Tube ◽  
High Reliability ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Interaction Point ◽  
Time Step ◽  
Point Tracking

Abstract In numerical simulations of hydroturbine systems, the fluid in the draft tube keeps alternating between free surface flow condition and pressured flow condition. This combination of free surface flow model and pressured flow model has been a focus of researchers. Because of the huge difference in pressure wave speed, the two models differ much in terms of meshing even in the same method. To track the interaction point between free surface flow and pressured flow, a type of interaction point tracking method (IPTM) is proposed, which is based on the method of characteristics. Using a controllable iteration to solve the controlling equations of the boundary conditions, the concrete interaction point can be tracked accurately at each time step. The method is validated in an actual turbine draft tube and compared with experimentally measured data. The results show that IPTM is equipped with high reliability and offers some advantages compared to the other existing methods.

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