Intense bed-load due to a sudden dam-break

2013 ◽  
Vol 731 ◽  
pp. 579-614 ◽  
Author(s):  
Benoit Spinewine ◽  
Hervé Capart
Keyword(s):  
Piecewise Linear ◽  
Constitutive Relations ◽  
Free Surface Flow ◽  
Light Sheet ◽  
Surface Flow ◽  
Dam Break ◽  
Bed Load ◽  
Theoretical Predictions ◽  
Yield Time ◽  
Theory Yield

AbstractIntense bed-load, or sheet flow, occurs when a free-surface flow of water drives a thick, rapidly sheared layer of water and grains over an erodible granular bed. We examine here the transient case where flow is induced by a sudden dam-break. Aiming for greater detail than achieved previously, we investigate this case using experiment and theory. The experiments combine particle tracking velocimetry (PTV) with a novel method of concentration measurement based on recording the penetration depth of a laser light sheet. The theory incorporates more vertical detail into the shallow water equations by using piecewise linear profiles of velocity and granular concentration, constrained by constitutive relations proposed recently for intense bed-load. These relations account for Coulomb yield at the bed, immersed granular collisions at the base, and equilibration of shear rate and density stratification across the bed-load layer. Using these approaches, both experiment and theory yield time- and depth-resolved profiles of velocity and granular concentration in addition to longitudinal wave profiles. Without any parameter adjustment, the theoretical predictions are in good agreement with the experimental measurements.

scholarly journals NUMERICAL AND EXPERIMENTAL STUDY OF DAM-BREAK FLOOD PROPAGATION AND ITS IMPLICATION TO SEDIMENT EROSION

2012 ◽  
Vol 1 (33) ◽  
pp. 7
Author(s):  
Hung-Chu Hsu ◽  
A. Torres-Freyermuth ◽  
Tian-Jian Hsu ◽  
Hwung-Hweng Hwung
Keyword(s):  
Free Surface ◽  
Sediment Transport ◽  
Numerical Model ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Transport Processes ◽  
Dam Break ◽  
Navier Stokes ◽  
Suspended Sediment Transport ◽  
Initial Stage

Regarding the hydrodynamics, within the past two decades it has become popular in numerical modeling of free-surface flow to adopt a Reynolds-averaged Navier-Stokes approach, where the volume of fluid (VOF) method is utilized to track the evolution of free-surface. However, this robust numerical model has not been widely applied to the study of sediment transport processes. In this study, we shall extend the numerical model to simulate suspended sediment transport and study the erosion pattern during the initial stage of the dam break flow. We also conducted a series of experiments in a horizontal channel of rectangular section and recorded the snap shots of surface profiles of a dam- break wave during the initial stage of dam-break. Measured data is utilized here to study the hydrodynamics and to validate the numerical model.

scholarly journals A LATTICE BOLTZMANN APPROACH FOR THREE-DIMENSIONAL TSUNAMI SIMULATION BASED ON THE PLIC-VOF METHOD

2018 ◽  
pp. 90
Author(s):  
Kenta Sato ◽  
Shunichi Koshimura
Keyword(s):  
Lattice Boltzmann ◽  
Piecewise Linear ◽  
Computational Cost ◽  
Three Dimensional ◽  
Simulation Models ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Fluid Simulation ◽  
Benchmark Problems ◽  
Tsunami Simulation

Free surface flow problems occur in numerous disaster simulations, such as tsunamis inland penetration in urban area. Simulation models for these problems have to be non-hydrostatic and three-dimensional because of the strong non-linearity and higher-order physical phenomena. Despite all the progress in the modern computational fluid dynamics, such simulations still present formidable challenges both from numerical and computational cost point of view. The lattice Boltzmann method (LBM) has been attracting attention as an alternative fluid simulation tool to overcome the problems. In current study, LBM for three-dimensional tsunami simulations is developed which are coupled with the piecewise linear interface calculation with the Volume of Fluid (VOF) approach. This model is for an efficient three-dimensional tsunami simulation by a one-fluid formulation, where the lattice Boltzmann equation is assigned to solve for a single virtual fluid. Various benchmark problems are also carried out to validate the utility of the proposed models in term of coastal engineering.

Volume Tracking on Triangular Meshes

2002 ◽  
Author(s):  
Khosro Shahbazi ◽  
Marius Paraschivoiu ◽  
Javad Mostaghimi
Keyword(s):  
Complex Geometry ◽  
Piecewise Linear ◽  
Time Integration ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Tracking Algorithm ◽  
Material Distribution ◽  
Triangular Meshes ◽  
Order Accuracy ◽  
First Order

This paper investigates a volume tracking algorithm on triangular meshes, associated with modeling free surface flow and multi phase flow on complex geometry. The volume tracking algorithm is divided into two main tasks. First, a piecewise linear reconstructing the interface is used to approximate the interface at each interfacial cell with a segment line. The convergence study of this approach reveals first order accuracy in reproducing a circular material distribution. Second, a Lagrangian time integration accompanied by a full remap is carried out in order to advect volume material in time. A circular material distribution is tested under simple translation and rotation. Visualization of results shows that the circular shape is conserved while first order accuracy is observed.

A Laboratory Study of Sediment Transport in Free Surface Flow

2005 ◽  
Author(s):  
Alfred D. Parr
Keyword(s):  
Sediment Transport ◽  
Transport Phenomena ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Local Scour ◽  
Bridge Piers ◽  
Bed Load ◽  
Dimension Lumber ◽  
Hands On ◽  
Bed Forms

This paper discusses an undergraduate fluid mechanics laboratory session. The lab allows the students to observe various sediment transport phenomena in a hands-on manner. The experiments are performed in a glass-walled, tilting sediment flume. The following sediment transport phenomena are created and observed by the students — bed load, suspended load, bed forms (ripples, dunes, antidunes...), surface waves over various bed forms and local scour at flow obstructions including bridge piers and abutments. Students are able to observe local scour using PVC pipes for bridge piers and dimension lumber for abutment scour. Since the flume is 12.2-m long, a large group of students can spread out along both sides of the flume to observe bed forms and to perform local scour tests.

3D Volume-of-Fluid (VOF) Based Simulation of Water Impact Problem Using Navier-Stokes Computations

2015 ◽  
Author(s):  
Van-Tu Nguyen ◽  
Warn-Gyu Park
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Free Surface Flow ◽  
Volume Of Fluid ◽  
Water Entry ◽  
Surface Flow ◽  
Dam Break ◽  
Navier Stokes ◽  
Water Impact ◽  
Impact Problem

In this paper, a three-dimensional (3D) numerical investigation of dam-break and water entry problems with emphasis on the water impact loading is presented. Flow fields of incompressible viscous fluids are solved using unsteady Navier-Stokes equations (NS). Pseudo-time derivatives are introduced into the equations to improve computational efficiency. The interface between two phases is tracked using a volume-of-fluid (VOF) interface tracking algorithm developed in a generalized curvilinear coordinate system. The accuracy and capability of the numerical model for free surface flow simulations are demonstrated by using experiments of the dam-break flow over a horizontal dry bed. The water impact problem has been analyzed by free falling water entry of a hemisphere and a cone. Comparisons between the obtained solutions, the experimental data and the results of other numerical simulations in the literature are presented exhibiting good agreement.

Analysis of Polygonal Vortex Flows in a Cylinder with a Rotating Bottom

2021 ◽  
Vol 11 (3) ◽  
pp. 1348
Author(s):  
A. Rashkovan ◽  
S.D. Amar ◽  
U. Bieder ◽  
G. Ziskind
Keyword(s):  
Experimental Studies ◽  
Free Surface Flow ◽  
Careful Analysis ◽  
Numerical Approach ◽  
Surface Flow ◽  
Initial Water ◽  
Eddy Simulation ◽  
Disk Rotation ◽  
Inner Radius ◽  
Liquid Flows

The present paper provides a physically sound numerical modeling of liquid flows experimentally observed inside a vertical circular cylinder with a stationary envelope, rotating bottom and open top. In these flows, the resulting vortex depth may be such that the rotating bottom disk becomes partially exposed, and rather peculiar polygon shapes appear. The parameters and features of this work are chosen based on a careful analysis of the literature. Accordingly, the cylinder inner radius is 145 mm and the initial water height is 60 mm. The experiments with bottom disk rotation frequencies of 3.0, 3.4, 4.0 and 4.6 Hz are simulated. The chosen frequency range encompasses the regions of ellipse and triangle shapes as observed in the experimental studies reported in the literature. The free surface flow is expected to be turbulent, with the Reynolds number of O(105). The Large Eddy Simulation (LES) is adopted as the numerical approach, with a localized dynamic Subgrid-Scale Stresses (SGS) model including an energy equation. Since the flow obviously requires a surface tracking or capturing method, a volume-of-fluid (VOF) approach has been chosen based on the findings, where this method provided stable shapes in the ranges of parameters found in the corresponding experiments. Expected ellipse and triangle shapes are revealed and analyzed. A detailed character of the numerical results allows for an in-depth discussion and analysis of the mechanisms and features which accompany the characteristic shapes and their alterations. As a result, a unique insight into the polygon flow structures is provided.

scholarly journals Laminar free-surface flow into a vertical cylinder

1975 ◽  
Vol 3 (1) ◽  
pp. 51-68 ◽  
Author(s):  
Thomas G. Smith ◽  
J.O. Wilkes
Keyword(s):  
Free Surface ◽  
Vertical Cylinder ◽  
Free Surface Flow ◽  
Surface Flow

scholarly journals Time-resolved PIV measurements of a deflected submerged jet interacting with liquid-gas and liquid-liquid interfaces

2021 ◽  
Author(s):  
Stefan Puttinger ◽  
Mahdi Saeedipour
Keyword(s):  
Liquid Layer ◽  
Large Scale ◽  
Free Surface Flow ◽  
Industrial Applications ◽  
Liquid Pool ◽  
Surface Flow ◽  
Two Phase ◽  
Time Resolved ◽  
Submerged Jet ◽  
Major Interest

AbstractThis paper presents an experimental investigation on the interactions of a deflected submerged jet into a liquid pool with its above interface in the absence and presence of an additional lighter liquid. Whereas the former is a free surface flow, the latter mimics a situation of two stratified liquids where the liquid-liquid interface is disturbed by large-scale motions in the liquid pool. Such configurations are encountered in various industrial applications and, in most cases, it is of major interest to avoid the entrainment of droplets from the lighter liquid into the main flow. Therefore, it is important to understand the fluid dynamics in such configurations and to analyze the differences between the cases with and without the additional liquid layer. To study this problem, we applied time-resolved particle image velocimetry experiments with high spatial resolution. A detailed data analysis of a small layer beneath the interface shows that although the presence of an additional liquid layer stabilizes the oscillations of the submerged jet significantly, the amount of kinetic energy, enstrophy, and velocity fluctuations concentrated in the proximity of the interface is higher when the oil layer is present. In addition, we analyze the energy distribution across the eigenmodes of a proper orthogonal distribution and the distribution of strain and vortex dominated regions. As the main objective of this study, these high-resolution time-resolved experimental data provide a validation platform for the development of new models in the context of the volume of fluid-based large eddy simulation of turbulent two-phase flows.

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