Turbulence in a channel with a patchy submerged canopy: the impact of spatial configuration

Journal of Fluid Mechanics, Journal Year: 2025, Volume and Issue: 1006

Published: March 7, 2025

This study investigates how the spatial configuration of submerged three-dimensional patches vegetation impacts turbulence. Laboratory experiments were conducted in a channel with model configured different patch area densities ( $\phi _{p}$ ), representing bed fraction occupied by patches, ranging from 0.13 to 0.78, and patterns transitioning two dimensional (channel-spanning patches) three (laterally unconfined patches). These configurations produced range flow regimes within canopy, wake interference skimming flow. At low density _{p}\lt0.5$ turbulence canopy increased increasing regardless configuration, while at high _{p}\gt0.5$ relationship between depended on patches. For same density, smaller lateral gaps generated stronger canopy. The relative contributions shear production also varied densities, dominated over production, was more dominant due an enhanced layer top reduced mean velocity A new predictive for channel-averaged turbulent kinetic energy (TKE) developed as function velocity, geometry, which showed good agreement measured TKE.

Language: Английский

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Wave attenuation in a partially vegetated flume

Limnology and Oceanography, Journal Year: 2025, Volume and Issue: unknown

Published: March 21, 2025

Abstract Wave attenuation in partially vegetated aquatic environments remains an underexplored area of research. This study addresses this gap by conducting laboratory experiments to examine the influence vegetation on wave dynamics. The wavelength‐to‐vegetation spacing ratio is essential quantifying behavior waves within and around areas. Laboratory measure height variations along longitudinal transverse directions areas partial coverage. Our results indicate that, for experimental cases where patches extended only a few wavelengths propagation direction, when greater than one, across flume approaches uniformity; contrast, smaller occurs predominantly region. advances our understanding complex interactions between vegetation, providing foundation further engineering ecological

Language: Английский

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Turbulence enhances wave attenuation of seagrass in combined wave–current flows

Proceedings of the National Academy of Sciences, Journal Year: 2025, Volume and Issue: 122(6)

Published: Feb. 7, 2025

The wave attenuation properties of seagrasses are key to accurately predict how effective these plants at protecting coasts from erosion and floods. While recent studies have significantly advanced the understanding seagrass in pure-wave conditions, presence a current introduces several complications that yet be fully explored. In present study, we quantify canopies parallel direction propagation via experiments conducted with dynamically scaled mimics installed laboratory flume facility. dataset is largest its kind spans broad range properties, velocities, water depths, plant densities for total over 300 experiments. Using our experimental results, show commonly employed approach modeling as result vegetation drag works well conditions but underpredicts systematically when turbulence generated by interaction between canopy sufficiently strong. We then employ phenomenological arguments data identify nondimensional parameter effectively quantifies relative importance dictating overall observed attenuation. Moreover, propose simple physically based consistent proposed phenomenology can used applications coastal waters.

Language: Английский

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The Evolution of Hydrodynamic Intensities and Sediment Erosion Along Submerged Aquatic Vegetation

Water Resources Research, Journal Year: 2025, Volume and Issue: 61(3)

Published: March 1, 2025

Abstract Submerged aquatic vegetation, a key component of these solutions, plays crucial role in coastal and river ecosystems by reducing flow velocity preventing sediment erosion. Although extensive research has explored the profiles submerged meadows covering entire channels, natural vegetation distributions are often patchy interact with three‐dimensional fields. some studies have shown that patches improve deposition, effects 3‐D on structures transport remain unclear. This study aims to investigate physical mechanisms underlying flow‐vegetation‐sediment interactions. By combining theoretical derivations laboratory experiments, we examine impact artificial development unidirectional flows. Our results reveal strong correlation between turbulent kinetic energy, characteristics, co‐evolved sand bedforms. The root mean square error our turbulence prediction model, which includes factors bed friction, is less than 10% fully developed region. Furthermore, presence meadows, TKE outside increases triple levels found within meadow, significantly influencing bedform increasing roughness height 5 13 times. characteristics such as ripple length steepness, conversely act indicator near‐bed strength. Additionally, local scours around stems overall correlate hydrodynamic intensities. As density coverage increase, magnitude decreases.

Language: Английский

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Wave damping by flexible marsh plants influenced by current

Physical Review Fluids, Journal Year: 2021, Volume and Issue: 6(10)

Published: Oct. 13, 2021

We develop a wave damping model based on prediction of current- and wave-induced force individual plants. The captures the influence reconfiguration forces, impact current group velocity, modification in-canopy time-mean orbital velocity associated with canopy drag, all which affect dissipation by vegetation. explains why weak reduces while strong increases dissipation, as observed both in present previous studies. Further, we explore plant flexibility leaf morphology over wide range to ratio.

Language: Английский

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Wave damping by seagrass meadows in combined wave‐current conditions

Limnology and Oceanography, Journal Year: 2022, Volume and Issue: 67(7), P. 1554 - 1565

Published: May 25, 2022

Abstract Laboratory experiments using an artificial seagrass meadow modeled after Zostera marina measured the impact of following currents on meadow‐induced wave decay as a function imposed current velocity , and Cauchy number which is ratio hydrodynamic drag force to restoring due blade stiffness. For small wave‐induced reconfiguration individual blades addition enhanced reconfiguration, decreased relative pure conditions. In contrast, when was large did not significantly enhance or damping. Due canopy drag, within submerged meadow, smaller than depth‐averaged better prediction achieved relevant velocity. The validated predictions based modified number, defined for combined waves in‐canopy . Practical assumptions facilitate in field are discussed validated.

Language: Английский

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A simple prediction of time-mean and wave orbital velocities in submerged canopy

Journal of Fluid Mechanics, Journal Year: 2024, Volume and Issue: 982

Published: Feb. 29, 2024

Flow within submerged canopies influences the transport of nutrients, sediment, pollutants, plant seeds and settlement larvae. To improve our understanding mass canopies, a simple model is proposed to predict total time-varying velocity rigid (representing coral reefs) flexible seagrasses saltmarshes). The divides momentum equations into canopy layer free-stream layer. difference in time derivative between two layers balanced by sum shear stress drag, both which depend on in-canopy velocity. present extended developed for steady current combined wave conditions without additional calibrating coefficients. agreed well with measured several previous studies. Importantly, significantly improved accuracy time-mean prediction, reduced root mean square error more than 50 %, compared models. revealed that addition waves can decrease

Language: Английский

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Hydrodynamics affected by submerged vegetation with different flexibility under unidirectional flow

Frontiers in Marine Science, Journal Year: 2023, Volume and Issue: 9

Published: Jan. 10, 2023

Submerged vegetation changes the hydrodynamic characteristics of rivers, lakes, wetlands, and coastal zones. However, only a few studies have focused on effect flexible submerged under unidirectional flow. Therefore, laboratory experiments were conducted to study effects with different flexibility flow structure turbulence The results showed that reconfiguration coordination wave motion redistribute velocity, Reynolds stress, turbulent kinetic energy inside outside canopy. With gradual decrease in deflection height vegetation, differences dimensionless mixed layer thickness, bulk drag coefficient, averaged energy, contribution rate its shear production term for canopy also decrease; trend penetration depth stress is opposite. Based budget equation, model (TKE model) was established, which can be used predict within Here, scaling factor determined by Cauchy number. TKE applied conditions flexibilities high accuracy. It simple method vegetation-induced sediment material transport influence flexibility.

Language: Английский

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Flow velocity evolution through a floating rigid cylinder array under unidirectional flow

Journal of Hydrology, Journal Year: 2022, Volume and Issue: 617, P. 128915 - 128915

Published: Dec. 14, 2022

Language: Английский

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Performance enhancement of hydrodynamic piezoelectric energy harvester by array disturbance

Energy Conversion and Management, Journal Year: 2023, Volume and Issue: 298, P. 117775 - 117775

Published: Oct. 25, 2023

Language: Английский

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