scholarly journals SYNOPTIC OBSERVATIONS OF SAND MOVEMENT

1970 ◽  
Vol 1 (12) ◽  
pp. 49
Author(s):  
David B. Duane
Keyword(s):  
Sediment Transport ◽  
Los Angeles ◽  
Surf Zone ◽  
Atomic Energy Commission ◽  
National Laboratory ◽  
Breaking Waves ◽  
Army Corps ◽  
Corps Of Engineers ◽  
Oak Ridge ◽  
Synoptic Observations

The U S Army Corps of Engineers' Coastal Engineering Research Center, in cooperation with the Atomic Energy Commission, initiated a multi-agency program to create a viable radioisotopic sand tracing (RIST) program Other agency participants in this program have been the Los Angeles District, Corps of Engineers, U S Air Force (First Strategic Aerospace Division), U S Navy (Pacific Missile Range), U S Army Mobility Equipment Command, National Aeronautics and Space Administration, and the State of California (Dept of Navigation and Ocean Development) CERC, together with the AEC's Oak Ridge National Laboratory has developed tagging procedures, hardware development, field surveys and data handling techniques that permit collection and analysis of over 12,000 bits of information per hour over a survey track of approximately 18,000 feet Data obtained with the RIST system can be considered as nearly synoptic observations of sediment transport m a single environmental zone or in adjacent beach, surf and offshore zones Using sand tagged with isotopes of gold, experiments have been carried out at several sites on the California coast Surf, Point Conception area, Point Mugu, and Oceanside Data from the studies carried out in beach areas unmodified by littoral barriers indicate that under a given set of wave conditions the alongshore velocity of sediment transport differs from zone to zone such that transport seaward of peakmg-breaking waves < transport on the beach face < transport in the plunge and surf zone Because of these differences, tracing surveys confined solely to the foreshore or offshore zones produce data only partially indicative of transport in the zone of immediate concern to coastal engineers.

scholarly journals OBSERVATIONS OF HORIZONTAL AND VERTICAL SEDIMENT FLUXES ON A SANDBAR IN THE SUSPENDED AND SHEET FLOW LAYERS

2018 ◽  
pp. 30
Author(s):  
Ryan S. Mieras ◽  
Jack A. Puleo ◽  
Dylan Anderson ◽  
Daniel T. Cox ◽  
Tian-Jian Hsu ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Surf Zone ◽  
Breaking Waves ◽  
Suspended Load ◽  
Bed Load ◽  
Sheet Flow ◽  
Coastal Morphology ◽  
Sediment Fluxes ◽  
Wave Forcing ◽  
Transport Component

The majority of prior sandbar migration studies have been conducted from the morphological standpoint, whereby, (i) bathymetric profiles are recorded over periods of time ranging from days to decades, at frequencies ranging from hourly to yearly (Ruessink et al., 2003), and (ii) hydrodynamic observations typically consist of far-field wave and environmental conditions. Subsequent modeling efforts have generally focused on tuning parameters in the sediment transport formulations (suspended load and bed load) to maximize model skill in predicting observed beach profiles over time (Fernández-Mora et al., 2015; Hoefel and Elgar, 2003). However, little emphasis at the operational level has been placed on tuning coastal morphology models to the true relative contributions of the physical processes (e.g. suspended load, bed load and/or sheet flow) that drive the changing bathymetry. This is due, in part, to the lack of detailed sediment transport observations (field and lab) under realistic wave forcing conditions and spatially variable bathymetry. Such a modeling approach leads to the improper quantification (magnitude and/or direction) of each modeled sediment transport component under skewed-asymmetric and/or breaking waves, often observed in the surf zone. The present study aims to better understand the physical mechanisms responsible for driving cross-shore sediment transport over a sandbar by quantifying (a) the vertical exchange of sediment at the near-bed interface (i.e. pick-up layer), and (b) intra-wave horizontal sediment fluxes in the suspended load and sheet layers.

scholarly journals MODELING COARSE SAND TRANSPORT UNDER SKEWED OSCILLATORY FLOW USING A CFD-DEM APPROACH

2018 ◽  
pp. 18
Author(s):  
Yashar Rafati ◽  
Zhen Cheng ◽  
Xiao Yu ◽  
Tian-Jian Hsu ◽  
Joseph Calantoni
Keyword(s):  
Sediment Transport ◽  
Surf Zone ◽  
Regional Scale ◽  
Breaking Waves ◽  
Coarse Sand ◽  
Sand Transport ◽  
Sheet Flow ◽  
Two Phase ◽  
Coastal Morphology ◽  
Flow Transport

Onshore/offshore sediment transport in the nearshore is an important mechanism driving the evolution of coastal morphology. The so-called sheet flow is a transport regime, in which the flow forces are intense such that a large amount of transport occurs in a concentrated layer near the bed. Onshore transport is often associated with flow skewness/asymmetry. In the nearshore zone, due to the bottom slope and wave shoaling, the wave velocity tends be onshore skewed before breaking in the surf zone. For breaking waves, the velocity asymmetry (or acceleration skewness) may also play a key role in determining net sediment transport. Understanding the net sediment transport rate in response to wave skewness/asymmetry is fundamental to a better prediction of sediment transport in regional scale morphodynamic models. In this study, we used an Euler-Lagrange two-phase model to study sheet flow transport of coarse sand under oscillatory flows subject to velocity/acceleration skewness.

scholarly journals Ohio River Navigation Investment Model: Requirements and Model Design

1998 ◽  
Vol 1620 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Michael S. Bronzini ◽  
T. Randall Curlee ◽  
Paul N. Leiby ◽  
Frank Southworth ◽  
Michael S. Summers
Keyword(s):  
National Laboratory ◽  
Cost Savings ◽  
River System ◽  
Integrated Approach ◽  
Investment Model ◽  
Army Corps ◽  
Ohio River ◽  
Investment Projects ◽  
Oak Ridge ◽  
The Many

Oak Ridge National Laboratory is assisting the U.S. Army Corps of Engineers in improving its economic analysis procedures for evaluation of inland waterway investment projects along the Ohio River system. The context and design of an integrated approach to calculating the systemwide benefits from alternative combinations of lock and channel improvements, providing an ability to project the cost savings from proposed waterway improvements in capacity and reliability for up to 50 years into the future, is described. The design contains an in-depth treatment of the levels of risk and uncertainty associated with different multiyear lock and channel improvement plans, including the uncertainty that results from a high degree of interaction between the many different waterway system components.

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