scispace - formally typeset
Search or ask a question
Author

Francis C. K. Ting

Bio: Francis C. K. Ting is an academic researcher from South Dakota State University. The author has contributed to research in topics: Breaking wave & Turbulence. The author has an hindex of 17, co-authored 39 publications receiving 2375 citations. Previous affiliations of Francis C. K. Ting include Texas A&M Transportation Institute & Texas A&M University.

Papers
More filters
Journal ArticleDOI
TL;DR: In this paper, the mean flow and turbulence in a wave flume for a spilling breaker and a plunging breaker were studied, and the results indicated that there are fundamental differences in the dynamics of turbulence between spilling and plunging breakers, which can be related to the processes of wave breaking and turbulence production.

384 citations

Journal ArticleDOI
TL;DR: In this paper, a new apparatus called the EFA (Erosion Function Apparatus) has been built and tested to measure the erosion rate of fine grained soils.
Abstract: Scour is the number one cause of bridge failures. Scour in coarse grained soils (sand, gravel) is relatively well known, but scour in fine grained soils (silt, clay) and weak rock is not. In coarse grained soils, scour takes place very rapidly and the scour rate is rarely an issue because one flood is likely to create the maximum scour depth. In fine grained soils, the scour process is much slower; as a result, even after a hundred years, a bridge may not experience the maximum depth of scour. Therefore, in fine grained soils it becomes necessary to predict the rate at which scour takes place. A new apparatus called the EFA (Erosion Function Apparatus; 〈http://tti.tamu.edu/geotech/scour〉) has been built and tested to measure the erosion rate of fine grained soils; the EFA can also be used to measure the erosion rate of coarse grained soils if necessary. The end of a Shelby tube sample from the bridge site is fitted through a tight opening at the bottom of a pipe with a rectangular cross section. Water flo...

382 citations

Journal Article
TL;DR: In this article, the mean flow and turbulence in a wave flume for a spilling breaker and a plunging breaker were studied, and the results indicated that there are fundamental differences in the dynamics of turbulence between spilling and plunging breakers, which can be related to the processes of wave breaking and turbulence production.
Abstract: Undertow and turbulence in the surf zone have been studied in a wave flume for a spilling breaker and a plunging breaker. Fluid velocities across a 1 on 35 sloped false bottom were measured using a fiber-optic laser-Doppler anemometer, and wave decay and set-up were measured using a capacitance wave gage. The characteristics of mean flow and turbulence in spilling versus plunging breakers were studied. The mean flow is the organized wave-induced flow defined as the phase average of the instantaneous velocity, while the turbulence is taken as the deviations from the phase average. It was found that under the plunging breaker turbulence levels are much higher and vertical variations of undertow and turbulence intensity are much smaller in comparison with the spilling breaker. It was also found that turbulent kinetic energy is transported seaward under the spilling breaker and landward under the plunging breaker by the mean flow. The study indicates that there are fundamental differences in the dynamics of turbulence between spilling and plunging breakers, which can be related to the processes of wave breaking and turbulence production. It is suggested that the types of beach profile produced by storm and swell waves may be the results of different relationships between mean flow and turbulence in these waves.

363 citations

Journal ArticleDOI
TL;DR: In this article, a new method called SRICOS is proposed to predict the scour depth z versus time t around a cylindrical bridge pier of diameter D founded in clay.
Abstract: A new method called SRICOS is proposed to predict the scour depth z versus time t around a cylindrical bridge pier of diameter D founded in clay. The steps involved are: (1) taking samples at the bridge pier site; (2) testing them in an erosion function apparatus to obtain the scour rate z versus the hydraulic shear stress applied τ; (3) predicting the maximum shear stress τmax, which will be induced around the pier by the water flowing at vo before the scour hole starts to develop; (4) using the measured z versus τ curve to obtain the initial scour rate zi corresponding to τmax; (5) predicting the maximum depth of scour zmax for the pier; (6) using zi and zmax to develop the hyperbolic function describing the scour depth z versus time t curve; and (7) reading the z versus t curve at a time corresponding to the duration of the flood to find the scour depth that will develop around that pier. A new apparatus is developed to measure the z versus t curve of step 2, a series of advanced numerical simulations ...

321 citations

Journal ArticleDOI
TL;DR: In this article, the structure of turbulence in a spilling breaker has been studied experimentally based on the transport equation for turbulent kinetic energy (the k-equation), and it is found that diffusive transport plays the most important role in the distribution of turbulence, while advection is important mainly near the surface.

259 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: OpenFoam as discussed by the authors is a CFD library for solving free surface Newtonian flows using the Reynolds averaged Navier-Stokes equations coupled with a volume of fluid method.
Abstract: SUMMARY The open-source CFD library OpenFoam® contains a method for solving free surface Newtonian flows using the Reynolds averaged Navier–Stokes equations coupled with a volume of fluid method. In this paper, it is demonstrated how this has been extended with a generic wave generation and absorption method termed ‘wave relaxation zones’, on which a detailed account is given. The ability to use OpenFoam for the modelling of waves is demonstrated using two benchmark test cases, which show the ability to model wave propagation and wave breaking. Furthermore, the reflection coefficient from outlet relaxation zones is considered for a range of parameters. The toolbox is implemented in C++, and the flexibility in deriving new relaxation methods and implementing new wave theories along with other shapes of the relaxation zone is outlined. Subsequent to the publication of this paper, the toolbox has been made freely available through the OpenFoam-Extend Community. Copyright © 2011 John Wiley & Sons, Ltd.

852 citations

Journal ArticleDOI
TL;DR: In this paper, a nonlinear Reynolds stress model is employed to relate the Reynolds stresses and the strain rates of the mean flow for a single wave propagating over a long distance in a constant depth.
Abstract: This paper describes the development of a numerical model for studying the evolution of a wave train, shoaling and breaking in the surf zone. The model solves the Reynolds equations for the mean (ensemble average) flow field and the k–e equations for the turbulent kinetic energy, k, and the turbulence dissipation rate, e. A nonlinear Reynolds stress model (Shih, Zhu & Lumley 1996) is employed to relate the Reynolds stresses and the strain rates of the mean flow. To track free-surface movements, the volume of fluid (VOF) method is employed. To ensure the accuracy of each component of the numerical model, several steps have been taken to verify numerical solutions with either analytical solutions or experimental data. For non-breaking waves, very accurate results are obtained for a solitary wave propagating over a long distance in a constant depth. Good agreement between numerical results and experimental data has also been observed for shoaling and breaking cnoidal waves on a sloping beach in terms of free-surface profiles, mean velocities, and turbulent kinetic energy. Based on the numerical results, turbulence transport mechanisms under breaking waves are discussed.

801 citations

Book
01 Jun 2013
TL;DR: In this article, the granular solid: statics and elasticity of granular liquid and granular gases are discussed at the grain level, and the interaction between granular media, statics, elasticity and plasticity at the liquid level.
Abstract: Foreword 1. Introduction 2. Interactions at the grain level 3. The granular solid: statics and elasticity 4. The granular solid: plasticity 5. Granular gases 6. The granular liquid 7. Immersed granular media 8. Erosion and sediment transport 9. Geomorphology References Index.

433 citations

Journal ArticleDOI
TL;DR: In this paper, the erosion characteristics of soil in cracks in embankment dams are described by the erosion rate index, which measures the rate of erosion, and the critical shear stress, which represents the minimum shear stresses when erosion starts.
Abstract: The slot erosion test and the hole erosion test have been developed to study the erosion characteristics of soil in cracks in embankment dams. The erosion characteristics are described by the erosion rate index, which measures the rate of erosion, and the critical shear stress, which represents the minimum shear stress when erosion starts. Values of the erosion rate index span from 0 to 6, indicating that soils can differ in their rates of erosion by up to 10 6 times. The rate of erosion is shown to be dependent on the soil fines and clay sized content, plasticity, and dispersivity; compaction water content, density and degree of saturation; and clay mineralogy, and possibly the presence of cementing materials such as iron oxides. Coarse-grained, noncohesive soils, in general, erode more rapidly and have lower critical shear stresses than fine-grained soils. Knowledge of the erosion characteristics of the soil in the core of an embankment dam aids in the assessment of the likelihood of dam failure due to piping erosion.

409 citations

Journal ArticleDOI
TL;DR: In this paper, a new apparatus called the EFA (Erosion Function Apparatus) has been built and tested to measure the erosion rate of fine grained soils.
Abstract: Scour is the number one cause of bridge failures. Scour in coarse grained soils (sand, gravel) is relatively well known, but scour in fine grained soils (silt, clay) and weak rock is not. In coarse grained soils, scour takes place very rapidly and the scour rate is rarely an issue because one flood is likely to create the maximum scour depth. In fine grained soils, the scour process is much slower; as a result, even after a hundred years, a bridge may not experience the maximum depth of scour. Therefore, in fine grained soils it becomes necessary to predict the rate at which scour takes place. A new apparatus called the EFA (Erosion Function Apparatus; 〈http://tti.tamu.edu/geotech/scour〉) has been built and tested to measure the erosion rate of fine grained soils; the EFA can also be used to measure the erosion rate of coarse grained soils if necessary. The end of a Shelby tube sample from the bridge site is fitted through a tight opening at the bottom of a pipe with a rectangular cross section. Water flo...

382 citations