scholarly journals Estimates of Discharge Coefficient in Levee Breach Under Two Different Approach Flow Types

2019 ◽  
Vol 11 (8) ◽  
pp. 2374
Author(s):  
Seung Oh Lee ◽  
Kwang Seok Yoon ◽  
Jun Seon Lee ◽  
Seung Ho Hong
Keyword(s):  
Discharge Coefficient ◽  
Action Plan ◽  
Water Discharge ◽  
Primary Input ◽  
Inundation Area ◽  
Levee Breach ◽  
Levee Failure ◽  
Reservoir Type ◽  
Dynamics Simulations ◽  
River Type

The amount of released water (discharge) in a levee breach is a primary input variable to establish an emergency action plan for the area next to the levee. However, although several studies have been conducted, there is still no widely applicable discharge coefficient formula; this needs to be known to estimate discharge amount through an opening caused by a levee breach. Sometimes, the discharge coefficient developed for a sharp crested side weir is used to rate the discharge, but, in case of a levee breach, the resulting geometry and flow types are similar to that over a broad crested weir. Thus, in this study, two different openings—rectangular and trapezoidal shape—are constructed in the center of a levee at a height of 0.6m to replicate levee breach scenarios, and the effect of two different approach flow types—the river type approach and reservoir type approach—are explored to suggest a discharge coefficient formula applicable for discharge rating for a levee breach. The results show that the ratio of head above the bottom of an opening and the opening width is a key variable for calculating the discharge coefficient of a reservoir type, but the approach Froude number should also be considered for a river type approach. The measured data are used to improve rating equations and will be useful in the future to validate computational fluid dynamics simulations of wave propagation during levee failure into the inundation area.

An Experimental and Computational Investigation of Absolute Pressure Effects on Deposition in an Effusion Cooling Geometry

2020 ◽  
Author(s):  
Christopher P. Brown ◽  
Jeffrey P. Bons
Keyword(s):  
Discharge Coefficient ◽  
Pressure Ratio ◽  
Road Dust ◽  
Pressure Effects ◽  
Absolute Pressure ◽  
Flow Density ◽  
State University ◽  
Particle Trajectories ◽  
The Ohio State University ◽  
Dynamics Simulations

Abstract The effect of absolute pressure on deposition is studied in the High-Pressure Deposition Facility at The Ohio State University. Mass flow blockage trends are presented for the case of deposition in a single-wall flat plate effusion cooling geometry. Arizona Road Dust in the ranges of 0–10 μm and 0–3.5 μm is delivered to a 950 K coolant flow at a pressure ratio of 1.03 at absolute pressures ranging from 1 to 15.77 atm. The primary results indicate a non-linear decrease in blockage with increasing absolute pressure. Additional targeted experimental and companion computational fluid dynamics simulations are used to elucidate the relative importance of 3 physical mechanisms responsible for the trend with pressure: (1) the increase in effusion hole discharge coefficient (2) altered particle trajectories due to reduced effective Stokes and (3) altered erosion due to reduced effective Stokes. Results reveal that blockage and sticking rates are minimally affected by the changing velocity field due to the increase in discharge coefficient, thus the increased particle drag effect on particle trajectories and erosion due to changing flow density is the primary candidate. To support these conclusions, mesh morphing simulations of a 0–10 μm test are performed at 1 and 15.77 atm using the OSU Deposition Model, which captures both impact velocity and angle dependencies of deposition. The resulting structures and their unique characteristics are compared to experimental deposits, and the computational and experimental blockage histories support the conclusion that increased drag is the primary mechanism.

Anticipating California Levee Failure: The State of the Delta Levees and Government Preparation and Response Strategies for Protecting Natural Resources from Freshwater Oil Spills

2011 ◽  
Vol 2011 (1) ◽  
pp. abs112 ◽  
Author(s):  
Patricia Sanderson Port ◽  
Samuel A. Hoover
Keyword(s):  
Water Resources ◽  
Structural Integrity ◽  
Oil Spills ◽  
Public Works ◽  
Federal State ◽  
Response Strategies ◽  
Levee Breach ◽  
Levee Failure ◽  
System 2 ◽  
State And Local

ABSTRACT Seismic activity and other natural and human forces significantly threaten the structural integrity of Delta levee systems. Breached levees appreciably impact fresh water resources, damage crops and livestock, destroy homes, schools, public works, businesses and wild species habitat, among other vital, sensitive areas. Levee failure often leads to oil and petroleum contamination of freshwater resources, particularly in dense residential, agricultural and commercial areas protected by levee systems that depend upon such water resources for drinking, irrigation and industrial uses. San Joaquin Delta to illustrate selected impacts to a freshwater region jeopardized by levee failure, this paper will: 1) discuss the current state of the Delta levee systems and detail the fragility of the system and the potential consequences of major impacts - earthquakes and floods likely to jeopardize this system; 2) review issues concerning levee breach preparedness, including practices to maintain levee structure and promote levee rehabilitation; and 3) suggest a coordinated federal, state and local response to contain damage caused by a levee breach, with particular focus on oil and hazardous materials spill impacts. As with many levee systems, the issues presented by a levee breach to the Sacramento-San Joaquin Delta region are complex and require close, concerted federal, state and local participation, not only to rapidly and effectively respond to impacted areas, but to anticipate and avoid more massive levee failure. Employment of these levee protection and breach response measures will help defend, among other vital resources, domestic, agricultural and industrial water for use from oil, petroleum and other hazardous contaminants.

scholarly journals Flood Inundation Assessment Considering Hydrologic Conditions and Functionalities of Hydraulic Facilities

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1879
Author(s):  
Yuan-Heng Wang ◽  
Yung-Chia Hsu ◽  
Gene You ◽  
Ching-Lien Yen ◽  
Chi-Ming Wang
Keyword(s):  
Risk Analysis ◽  
Action Plan ◽  
Flood Management ◽  
Engineering System ◽  
Flood Inundation ◽  
Remedial Action ◽  
Inundation Area ◽  
Analysis Methods ◽  
Analysis Scheme ◽  
Remedial Action Plan

This study proposed a two-phase risk analysis scheme for flood management considering flood inundation losses, including: (1) simplified qualitative-based risk analysis incorporating the principles of failure mode and effect analysis (FMEA) to identify all potential failure modes associated with candidate flood control measures, to formulate a remedial action plan aiming for mitigating the inundation risk within an engineering system; and (2) detailed quantitative-based risk analysis to employ numerical models to specify the consequences including flood extent and resulting losses. Conventional qualitative-based risk analysis methods have shown to be time-efficient but without quantitative information for decision making. However, quantitative-based risk analysis methods have shown to be time- and cost- consuming for a full spectrum investigation. The proposed scheme takes the advantages of both qualitative-based and quantitative-based approaches of time-efficient, cost-saving, objective and quantitative features for better flood management in term of expected loss. The proposed scheme was applied to evaluate the Chiang-Yuan Drainage system located on Lin-Bien River in southern Taiwan, as a case study. The remedial action plan given by the proposed scheme has shown to greatly reduce the inundation area in both highlands and lowlands. These measures was investigated to reduce the water volume in the inundation area by 0.2 million cubic meters, even in the scenario that the flood recurrence interval exceeded the normal (10-year) design standard. Our results showed that the high downstream water stage in the downstream boundary may increase the inundation area both in downstream and upstream and along the original drainage channel in the vicinity of the diversion. The selected measures given by the proposed scheme have shown to substantially reduce the flood risk and resulting loss, taking account of various scenarios: short duration precipitation, decreased channel conveyance, pump station failure and so forth.

Structural dynamics of P-type ATPase ion pumps

2019 ◽  
Vol 47 (5) ◽  
pp. 1247-1257 ◽  
Author(s):  
Mateusz Dyla ◽  
Sara Basse Hansen ◽  
Poul Nissen ◽  
Magnus Kjaergaard
Keyword(s):  
Structural Dynamics ◽  
Single Molecule ◽  
New Technologies ◽  
Atp Hydrolysis ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Time Resolved ◽  
Dynamics Simulations ◽  
Types Of Information ◽  
P Type

Abstract P-type ATPases transport ions across biological membranes against concentration gradients and are essential for all cells. They use the energy from ATP hydrolysis to propel large intramolecular movements, which drive vectorial transport of ions. Tight coordination of the motions of the pump is required to couple the two spatially distant processes of ion binding and ATP hydrolysis. Here, we review our current understanding of the structural dynamics of P-type ATPases, focusing primarily on Ca2+ pumps. We integrate different types of information that report on structural dynamics, primarily time-resolved fluorescence experiments including single-molecule Förster resonance energy transfer and molecular dynamics simulations, and interpret them in the framework provided by the numerous crystal structures of sarco/endoplasmic reticulum Ca2+-ATPase. We discuss the challenges in characterizing the dynamics of membrane pumps, and the likely impact of new technologies on the field.

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