scholarly journals Experimental Study of Overland Flow through Rigid Emergent Vegetation with Different Densities and Location Arrangements

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1638 ◽  
Author(s):  
Yuting Wang ◽  
Huilan Zhang ◽  
Pingping Yang ◽  
Yunqi Wang
Keyword(s):  
Water Depth ◽  
Overland Flow ◽  
Maximum Velocity ◽  
Two Dimensions ◽  
Emergent Vegetation ◽  
Vegetation Density ◽  
Hydrodynamic Parameters ◽  
Flow Through ◽  
Rigid Emergent Vegetation ◽  
Vegetated Slopes

The effect of vegetation density on overland flow dynamics has been extensively studied, yet fewer investigations have focused on vegetation arrangements with different densities and position features. Flume experiments were conducted to investigate the hydrodynamics of flow through rigid emergent vegetation arranged in combinations with three densities (Dense, Middle, and Sparse) and three positions (summit, backslope, and footslope). This study focused on how spatial variations regulated hydrodynamic parameters from two dimensions: direction along the slope and water depth. The total hydrodynamic parameters of bare slopes were significantly different from those of vegetated slopes. The relationship between Re and f illustrated that Re was not a unique predictor of hydraulic roughness on vegetated slopes. In the slope direction, all hydrodynamic parameters on vegetated slopes exhibited fluctuating downward/upward trends due to the clocking effect before the vegetated area and the rapid conveyance effect in the vegetated area, whereas constant values were observed on bare slopes. The performance of hydrodynamics parameters suggested that the dense rearward arrangement (SMD) was the optimal vegetation pattern to regulate flow conditions. Specifically, the vertical profiles of the velocity and turbulence features of the SMD arrangement at different sections demonstrated the significant role of vegetation density in identifying the velocity layers along the water depth. The maximum velocity and Reynolds Stress Number (RSN) indicated the position where local scour was most likely to occur, which would improve our basic understanding of the mechanisms underlying hydraulic and soil erosion processes.

Qualification and Certification of Polyester Rope for Seabed Contact

2017 ◽  
Author(s):  
Øystein Gabrielsen ◽  
Kjell Larsen
Keyword(s):  
Water Flow ◽  
Water Depth ◽  
Test Method ◽  
Mooring System ◽  
Qualification Test ◽  
Mooring Lines ◽  
Norwegian Sea ◽  
Flow Through ◽  
Full Scale Tests ◽  
Certification Requirements

The Aasta Hansteen spar in the Norwegian Sea is designed to be moored with a taut polyester rope mooring system. The water depth at the field is 1300 meters, and due to the short installation season the most efficient hookup is with pre-installed mooring lines, which require the mooring lines to be laid down on the seabed. DNV certification does not allow seabed contact for polyester ropes unless proven that no soil ingress and damage takes place. To be able to certify the ropes Statoil developed a test method including contact with soil, rope movement and forced water flow through the filter construction. Full scale tests were performed with actual rope and Aasta Hansteen soil, both in laboratory and at site. This paper discusses the certification requirements and presents adequate qualification test together with results from testing.

scholarly journals Effects of vegetation lodging on overland runoff flow regime and resistance

2020 ◽  
Vol 20 (4) ◽  
pp. 1463-1473
Author(s):  
Jingzhou Zhang ◽  
Shengtang Zhang ◽  
Guibao Li ◽  
Ming Liu ◽  
Si Chen
Keyword(s):  
Flow Regime ◽  
Water Depth ◽  
Overland Flow ◽  
Resistance Coefficient ◽  
Soil Consolidation ◽  
Slope Engineering ◽  
Overland Runoff ◽  
Flow Propagation ◽  
Water Depths ◽  
Fluid Characteristics

Abstract Vegetation is a vital part of the natural environment. Variations in vegetation morphology produce changes in the mechanical and fluid characteristics of overland flow. Determining the effects of vegetation lodging on the overland runoff flow regime and resistance is a prerequisite for accurately simulating overland runoff and convergence, revealing the mechanism of overland flow propagation, and the design and management of vegetation protection, soil consolidation, and ecological slope engineering. To systematically study the effects of vegetation lodging on overland runoff, four planting vegetation lodging angles (α) and 10 test water depths were used to simulate experimental research with a 1.0% slope ratio. Experimental results show that the depth and state of vegetation inundation and the degree of lodging significantly influence the flow regime and resistance. Under the same water depth, higher values of α are associated with higher values of the flow velocity, Reynolds number, Froude number, and Darcy–Weisbach resistance coefficient (f), and lower values of the drag coefficient (CD). The overall result is enhanced turbulence in the flow field and weaker flow resistance. Numerical statistics and difference analysis indicate that, when the vegetation is non-submerged, a 10° increase in α produces a 9.30% decrease in f. In the submerged state, a 10° increase in α causes a 26.70% decrease in f. CD is greatly affected by the boundary water depth. Below some critical water depths, an increase of 10° in α reduces CD by 8.48%. Above the critical depth, a 10° increase in α decreases CD by 41.10%.

Drag coefficients for modeling flow through emergent vegetation in the Florida Everglades

2004 ◽  
Vol 22 (4-5) ◽  
pp. 237-248 ◽  
Author(s):  
Jonathan K. Lee ◽  
Lisa C. Roig ◽  
Harry L. Jenter ◽  
Hannah M. Visser
Keyword(s):  
Emergent Vegetation ◽  
Florida Everglades ◽  
Drag Coefficients ◽  
Flow Through ◽  
Modeling Flow

scholarly journals Usage of SIMWE model to model urban overland flood: a case study in Oslo

2020 ◽  
Vol 51 (2) ◽  
pp. 366-380 ◽  
Author(s):  
Hong Li ◽  
Hongkai Gao ◽  
Yanlai Zhou ◽  
Chong-Yu Xu ◽  
Rengifo Z. Ortega M. ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Water Depth ◽  
Large Scale ◽  
Overland Flow ◽  
Depth Maps ◽  
Physically Based ◽  
Spatially Distributed ◽  
Overland Flow Model

Abstract There has been a surge of interest in the field of urban flooding in recent years. However, current stormwater management models are often too complex to apply on a large scale. To fill this gap, we use a physically based and spatially distributed overland flow model, SIMulated Water Erosion (SIMWE). The SIMWE model requires only rainfall intensity, terrain, infiltration, and surface roughness as input. The SIMWE model has great potential for application in real-time flood forecasting. In this study, we use the SIMWE model at two resolutions (20 m and 500 m) for Oslo, and at a high resolution (1 m) at the Grefsen area, which is approximately 1.5 km2 in Oslo. The results show that the SIMWE model can generate water depth maps at both coarse and high resolutions. The spatial resolution has strong impacts on the absolute values of water depth and subsequently on the classification of flood risks. The SIMWE model at a higher spatial resolution produces more overland flow and higher estimation of flood risk with low rainfall input, but larger areas of risk with high rainfall input. The Grefsen case study shows that roads act as floodways, where overland flow accumulates and moves fast.

Investigation of flow resistance exerted by rigid emergent vegetation in open channel

2019 ◽  
Vol 67 (3) ◽  
pp. 971-986 ◽  
Author(s):  
Antonino D’Ippolito ◽  
Agostino Lauria ◽  
Giancarlo Alfonsi ◽  
Francesco Calomino
Keyword(s):  
Flow Resistance ◽  
Open Channel ◽  
Emergent Vegetation ◽  
Rigid Emergent Vegetation

Routing overland flow through sinks and flats in interpolated raster terrain surfaces

2008 ◽  
Vol 34 (11) ◽  
pp. 1417-1430 ◽  
Author(s):  
Frank Kenny ◽  
Bryce Matthews ◽  
Kent Todd
Keyword(s):  
Overland Flow ◽  
Flow Through

scholarly journals High Resolution 3-D Simulations of Venting in 18650 Lithium-Ion Cells

2021 ◽  
Vol 9 ◽  
Author(s):  
Weisi Li ◽  
Vanessa León Quiroga ◽  
K. R. Crompton ◽  
Jason K. Ostanek
Keyword(s):  
Maximum Velocity ◽  
Lithium Ion ◽  
Current Collector ◽  
Thermal Runaway ◽  
Global Maximum ◽  
Collector Plate ◽  
Choked Flow ◽  
Velocity Magnitude ◽  
Lithium Ion Cell ◽  
Flow Through

High temperature gases released through the safety vent of a lithium-ion cell during a thermal runaway event contain flammable components that, if ignited, can increase the risk of thermal runaway propagation to other cells in a multi-cell pack configuration. Computational fluid dynamics (CFD) simulations of flow through detailed geometric models of four vent-activated commercial 18650 lithium-ion cell caps were conducted using two turbulence modeling approaches: Reynolds-averaged Navier-Stokes (RANS) and scale-resolving simulations (SRS). The RANS method was compared with independent experiments of discharge coefficient through the cap across a range of pressure ratios and then used to investigate the ensemble-averaged flow field for the four caps. At high pressure ratios, choked flow occurs either at the current collector plate when flow through the current collector plate is more restrictive or the positive terminal vent holes when flow through the current collector plate is less restrictive. Turbulent mixing occurred within the vent cap assembly, in the jets emerging from the vent holes, and in recirculating zones directly above the vent cap assembly. The global maximum turbulent viscosity ratio (μT/μ) of the MTI, LG MJ1, K2, and LG M36 caps at pressure ratio of P1/P2 = 7 were 4,575, 3,360, 3,855, and 2,993, respectively. SRS and RANS simulations showed that both velocity magnitude and fluctuating velocity magnitude were lower for vent holes which are obstructed by the burst disk. SRS showed high levels of fluctuating velocity in the jets, up to 48.5% of the global maximum velocity. The present CFD models and the resulting insights provide the groundwork for future studies to investigate how jet structure and turbulence levels influence combustion and heat transfer in propagating thermal runaway scenarios.

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