scholarly journals MODELING ALTERNATIVES FOR EROSION CONTROL AT MATAGORDA COUNTY,TEXAS, WITH GENCADE

2012 ◽  
Vol 1 (33) ◽  
pp. 97
Author(s):  
Ashley Frey ◽  
James Rosati, III ◽  
Kenneth J. Connell ◽  
Hans Hanson ◽  
Magnus Larson
Keyword(s):  
Engineering Design ◽  
Transport Model ◽  
Erosion Control ◽  
Shoreline Change ◽  
Sand Transport ◽  
Texas Coast

Matagorda Peninsula and Sargent Beach, Texas, USA, have experienced some of the highest rates of erosion along the Texas coast. In order to increase protection from tropical events and slow beach habitat erosion, several structural alternatives were studied. These alternatives were modeled with GenCade, a newly developed 1D shoreline change and sand transport model. GenCade was calibrated and validated over the 60 miles of shoreline in Matagorda County. Then separate GenCade grids and simulations were conducted for the structural alternatives at Matagorda Peninsula and Sargent Beach. At Matagorda Peninsula, different groin lengths and spacing between groins were modeled with and without beach fills and mechanical bypassing. The alternatives at Sargent Beach included detached breakwaters, groins, and beach fills. Although the process described in this paper only includes a small part of a more detailed study, these simulations helped lead to a recommendation of the selected alternatives for preliminary engineering design.

scholarly journals ESTIMATION USING A MOVABLE BED MODEL OF SHORELINE CHANGE CAUSED BY A RECLAMATION PROJECTED INTO THE SEA

1978 ◽  
Vol 1 (16) ◽  
pp. 111
Author(s):  
Shoji Sato ◽  
Hiroaki Ozasa
Keyword(s):  
Shoreline Change ◽  
Sand Transport ◽  
Observation Data ◽  
Model Studies ◽  
Passenger Traffic ◽  
Sea Bed ◽  
Field Observation Data ◽  
Transport Problems ◽  
Bed Material ◽  
Movable Bed

Recently, many local airports in Japan are considering to extend their runways, so accommodating passenger traffic. But most airports are obliged to extend their runways into the sea on account of the shortage of land and complaints from their neighbors about jet-plane noise. Tokushima Airport is one of such local airports, which is situated on the coast along the Kie-Suido Channel as shown Figure 1. The length of the runway of Tokushima Airport is 1500 m at percent, so a plan to extend the runway by 600 m into the sea has been proposed by the local government. However, Matsushige beach, where the airport is located, is now so seriously eroded that offshore breakwaters are being constructed in the south and the northern part is used for sea-bathing. Therefore, it is necessary to estimate the change of beach profiles, especially of the shoreline, caused by the extension of the runway, and to find countermeasures against unfavorable change. A movable bed model was constructed to estimate such changes, because no numerical simulation using a computer has been developed to estimate changes of a complicated beach topography. Of course, the universal dynamic similarity does not hold for model studies on sand transport problems. Therefore, the characteristics of sand transport at the site are first clarified through analysis of the field observation data, and then the model scale, bed material, and test waves are determined in such a manner that the topographic variation in the model sea bed will become similar to that in the prototype. But, in general, it is difficult to make all of the variations of the sea bed in the model similar to that in the prototype. In this model experiment, the long term changes of the shoreline has been taken as the most important phenomena to be reproduced in the model.

The analysis of relaxed criteria for erosion-control filters

1994 ◽  
Vol 31 (6) ◽  
pp. 829-840 ◽  
Author(s):  
H. Den Adel ◽  
M.A. Koenders ◽  
K.J. Bakker
Keyword(s):  
Mathematical Model ◽  
Grain Size ◽  
Granular Material ◽  
Key Words ◽  
Experimental Work ◽  
Transport Model ◽  
Base Material ◽  
Erosion Control ◽  
Sand Surface ◽  
Moving Base

To optimize the design of erosion-control filters a transport model is presented for moving base material in horizontally loaded filters that are not geometrically stable. Supporting experimental work is used to obtain the parameters in a descriptive quantitative mathematical model. A set of three fixed parameters describes most experiments. Exceptions are where the filter to base grain-size ratio is so small that geometrical obstruction takes place and where this ratio is so large that the turbulences in the flow cause the sand surface under the filter to ripple. The latter case is described with a slightly amended parameter to allow for the amount of fluctuation in the problem. Key words : filtration, transport, experiments, theory, granular material, barriers.

Sand transport model of barchan dune equilibrium

Sedimentology ◽  
1978 ◽  
Vol 25 (3) ◽  
pp. 307-338 ◽  
Author(s):  
A. D. HOWARD ◽  
J. B. MORTON ◽  
MOHAMED GAD-EL-HAK ◽  
DEBORAH B. PIERCE
Keyword(s):  
Transport Model ◽  
Sand Transport ◽  
Barchan Dune

scholarly journals Understanding the effects of seawall construction using a combination of analytical modelling and remote sensing techniques: Case study of Fansa, Gujarat, India

2017 ◽  
Vol 8 (3) ◽  
pp. 153-160 ◽  
Author(s):  
R. Balaji ◽  
S Sathish Kumar ◽  
Ankita Misra
Keyword(s):  
Remote Sensing ◽  
Analytical Model ◽  
Shoreline Change ◽  
Sand Transport ◽  
Longshore Sediment Transport ◽  
Near Shore ◽  
Remote Sensing Techniques ◽  
And Function ◽  
End Wall

The effect of seawall on the adjacent beaches and coastal dynamics has not been well documented in literature. The purpose and function of coastal structures, especially seawalls, have often been misunderstood, as in some cases, seawalls lead to coastal erosion, contrary to protecting the shoreline for which they are generally constructed. Seawalls have been reportedly causing changes in the near-shore process, specifically the sediment dynamics by affecting the onshore/offshore and, to some extent, the longshore sand transport. Therefore, it becomes imperative to understand the effect of seawalls on the adjoining beach to make sure more informed decisions are made on their installation. This article discusses the effects of seawall construction along the coast of Fansa, South Gujarat, India. A numerical model has been used to estimate the wave parameters along the selected coast, the results of which are subsequently utilized in an analytical model (parabolic shape model) to predict the end-wall effect. Independently, remote sensing datasets of CARTOSAT 1 with spatial resolution of 2.5 m are used to understand the shoreline change dynamics in this region, post-construction of this seawall. It is found empirically that the net longshore sediment transport rate is approximately 1.9 Mm3 per year along the coast. The results of the analytical model predict a maximum landward erosion of about 20 m and an alongshore erosion of 200 m on the down-drift side of the seawall. These estimations agree with those obtained by the remote sensing–based analysis, which estimates an erosion of approximately 40 m by the year 2014.

Research Progresses of Hydraulics for Extended Reach Drilling in China Part II: Hole Cleaning Monitoring and Hydraulic Extended Limit

2012 ◽  
Vol 524-527 ◽  
pp. 1553-1556
Author(s):  
Xiao Le Guo ◽  
Zhi Ming Wang ◽  
Zhi Hui Long
Keyword(s):  
Risk Analysis ◽  
Engineering Design ◽  
Transport Model ◽  
Calculation Model ◽  
Cuttings Transport ◽  
Monitoring Method ◽  
Hole Cleaning ◽  
Theoretical Support ◽  
Hydraulic Theory ◽  
Extended Reach Drilling

The extended reach drilling (ERD) is being adopted widely in China. But it also brought a series of technical difficulties because of its own characteristics. Some progresses were made after several years of hard work in China about Hydraulics for ERD. In the paper of “Research Progresses and Perspectives of Hydraulics for Extended Reach Drilling in China, Part I”, the author demenstrated part of these progresses including cuttings transport model and precise model of pressure loss calculation. In this paper, the part of rest were presented which inlcuding hydraulic extended limit calculation model and analysis and hole cleaning monitoring method for ERD. Based on the above studies, the author finally developed a system of hole cleaning monitoring and hydraulics design and its risk analysis which could provide theoretical support and useful tool for engineering design and risk analysis before drilling. These researches are helpful to ERD and have enriched the hydraulic theory of ERD.

scholarly journals ECO-SYSTEM BASED BEACH EROSION CONTROL BY BERM NOURISHMENT COMBINED WITH BURIED SAND TUBE

2018 ◽  
pp. 102
Author(s):  
Shinji Sato ◽  
Keisuke Murakami ◽  
Kunihiro Watanabe ◽  
Yuuichi Okamura ◽  
Shin Hashimoto ◽  
...  
Keyword(s):  
River Mouth ◽  
Erosion Control ◽  
Beach Erosion ◽  
Sand Transport ◽  
Wave Direction ◽  
Large Variability ◽  
Longshore Transport ◽  
The Pacific ◽  
Beach Sediments ◽  
Sand Nourishment

Miyazaki Coast is a 10 km stretch sandy beach between the Miyazaki Port and the Hitotsuse River, located south of Japan facing the Pacific Ocean. Significant beach erosion has been observed owing to the entrapment of sand in the harbor area and the blockage of longshore sand transport by the river mouth jetties. Sato et al. (ICCE 2010) estimated that the direction of the long-term longshore sand transport is to the southward on the basis of thermo-luminescence measurement of beach sediments. Continuous bathymetry surveys indicated the southward longshore sand transport rate at 200 thousand m3/year. However, a large variability of the incident wave direction suggested the variability in the direction of the longshore transport. Occasional attacks of typhoon storms appeared to accelerate the erosion. As a countermeasure to mitigate the erosion, sand nourishment has been introduced since 2008 with the amount of 50 to 80 thousand m3/year. Three groins were constructed to decrease the longshore transport. However, further erosion has been observed by typhoon storms even on the nourished area. This paper describes the results of on-site monitoring of waves, currents and topography change to understand the role of typhoon storms in beach erosion and to investigate the performance of eco-system based erosion control works.

scholarly journals Using Video Monitoring to Test a Fetch-Based Aeolian Sand Transport Model

2020 ◽  
Vol 8 (2) ◽  
pp. 110 ◽  
Author(s):  
Pam Hage ◽  
Gerben Ruessink ◽  
Zilla van Aartrijk ◽  
Jasper Donker
Keyword(s):  
Wind Velocity ◽  
Transport Model ◽  
Transport Rate ◽  
Beach Sand ◽  
Sand Transport ◽  
Winter Period ◽  
Aeolian Sand ◽  
Aeolian Transport ◽  
Aeolian Sand Transport ◽  
Strong Winds

Transport of beach sand to the foredune by wind is essential for dunes to grow. The aeolian sand transport rate is related to wind velocity, but wind-based models often overpredict this transport for narrow beaches (<100 m). To better predict aeolian sand transport, the fetch-based Aeolus model was developed. Here, we qualitatively test this model by comparing its transport-rate output to visual signs of aeolian transport on video imagery collected at Egmond aan Zee, the Netherlands, during a six-month winter period. The Aeolus model and the Argus images often agree on the timing of aeolian transport days, except when transport is small; that is not always visible on the Argus images. Consistent with the imagery (minimal signs of aeolian activity in strong winds), the Aeolus model sometimes predicts the actual transport to be smaller than the potential transport. This difference is largest when wind velocity is large, and its direction is cross-shore. Although transport limitations are not predicted to be common, the results suggest that their effect on the total transport in the study period was substantial. This indicates that the fetch distance should be taken into account when calculating aeolian transport for narrow beaches on longer timescales (>weeks).

scholarly journals Impacts of Fracture Roughness and Near-wellbore Tortuous on Proppant Transport Within Hydraulic Fractures

2021 ◽  
Author(s):  
Di Wang ◽  
Bingyang Bai ◽  
Bin Wang ◽  
Dongya Wei ◽  
Tianbo Liang
Keyword(s):  
Hydraulic Fracturing ◽  
Analytical Model ◽  
Volume Fraction ◽  
Transport Model ◽  
Sand Transport ◽  
Hydraulic Fractures ◽  
Fracture Roughness ◽  
Transport Velocity ◽  
Sand Bank ◽  
The Impact

Abstract For unconventional reservoirs hydraulic fracturing design, a greater fracture length is a prime factor to optimize. However, core observation results from Hydraulic Fracturing Test Site (HFTS) show the propped fractures are far less or shorter than expected which suggests the roughness and tortuous of hydraulic fractures are crucial to sand transport. In this study a transport model of sands is first built based on experimental measurements on the height and transport velocity of sand bank in fractures with predetermined width and roughness. The fracture roughness is quantified by using surface height integral. Then, three-dimensional simulations are conducted with this modified model to further investigate the impact of fractures tortuous on sand transport, from which an analytical model is established to estimate the propped length of hydraulic fractures at a certain pumping condition. Experiments results show that height of sand bank in roughness fracture is 20-50% higher than that in smooth. The height of sand bank decreases with the reduction of slurry velocity and increases with the sand diameters increasing. Sand sizes do little effect on the transport velocity of sand bank but the increase in slurry velocity and sand volume fraction can dramatically enhance the migration velocity of sand bank. The appearance of tortuous decreases the horizontal velocity of suspended particles and results in a higher sand bank compared with that in straight fractures. When the sand bank gets equilibrium at the tortuous position, it is easy to produce vortices. So, there is a significant height of sand bank change at the tortuous position. Moreover, sand plugging can occur at the entrance of the fractures, making it difficult for the sand to transport deep in fractures. This study explains why the propped length of fractures in HFTS is short and provides an analytical model that can be easily embedded in the fracturing simulation to fast calculate dimensions of the propped fractures network to predict length and height of propped fractures during fracturing.

Sign in / Sign up

Export Citation Format

Share Document