Laboratory investigation of Fallopia × bohemica fruits dispersal by watercourses

Rendu, Quentin; Mignot, Emmanuel; Rivière, Nicolas; Lamberti-Raverot, Barbara; Puijalon, Sara; Piola, Florence

doi:10.1007/s10652-017-9537-9

Cited by 4 publications

(3 citation statements)

References 19 publications

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“…It appears that the four velocity profiles are quite similar to each other and exhibit the expected global shape: a log region near the bed and a quite constant velocity profile further up in the water column in the bulk. In Fig.2, b/h ranges from 0.7 to 1.3 (with b the channel width and h the local water depth) and these profiles are indeed highly similar to typical velocity profiles of narrow and deep open-channel flows in the literature, as shown, for instance by [9] with b/h~1.1. Unfortunately, the ADV is not able to measure the details of the velocity profiles in the near-bed region to highlight the transitions between viscous, elastic (with additives) and logarithmic sub-layers.…”

Section: Smooth Bed Experimentssupporting

confidence: 77%

Reducing Darcy coefficient by using drag reduction methods in open-channel flows: Effect on discharge capacity and potential application to mitigate river flooding impact

Mignot

Rivière

Lefèvre³

et al. 2018

E3S Web Conf.

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Drag reduction by polymer addition is a common strategy used to minimize friction losses in pipe flows but has not been tested in river flows. Present paper then aims at measuring backwater curves and velocity profiles within smooth and rough bed flume configurations to assess the capabilities of such polymer addition to decrease the water depth with regards to the use of plain water and thus increase the channel conveyance. The inclusion of a limited amount of polymers proves to be able to reduce the typical Darcy-Weisbach friction coefficient with regards to plain water by a factor 2 in smooth bed conditions and a factor 1.5 in rough bed conditions. Moreover, the vertical profiles of streamwise velocity appear to be hardly affected by the addition of such polymers. Whether such drag reduction would still be effective in real watercourses remains unknown and would now require field experiments at larger scale.

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Section: Smooth Bed Experimentssupporting

confidence: 77%

Reducing Darcy coefficient by using drag reduction methods in open-channel flows: Effect on discharge capacity and potential application to mitigate river flooding impact

Mignot

Rivière

Lefèvre³

et al. 2018

E3S Web Conf.

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“…3). Differences in achene floatability may be related to different achene densities or surface tension (Carthey et al, 2016;Rendu et al, 2017). The proportion of achenes germinating in water differed between stands (30 to 95%), as well as the time to germination in water (from 2 to 20 days; Fig.4).…”

Section: Trait Variabilitymentioning

confidence: 99%

Achene traits involved in the water dispersal of the invasive Fallopia × bohemica complex: Variability and dispersal strategies

Lamberti-Raverot

Piola

Vallier

et al. 2019

Flora

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Secondary dispersal of terrestrial plant species through watercourses increases the dispersal range of floating seeds but their exposure to water may also challenge their viability and colonisation potential. Many terrestrial invasive species benefit from watercourses to extend their invasive range because water exposure can favour seed germination and early survival of seedlings for species sensitive to dry conditions and water flow enhances their dispersal distance downstream. Floatability, germination rate and survival after water exposure are seed traits involved in water dispersal and their variability may lead to different dispersal strategies. To address the question of the variability of achene traits involved in dispersal, we experimentally measured these three traits for Fallopia × bohemica achenes collected from 10 different stands. The floatability of achenes varied between stands from 2.5 to 5 days and their germination in water extended this period to 20 days through the emergence of floating seedlings. Germination proportions also differed between stands from 0.3 to 0.95 and were negatively related to the median germination time. Seedling survival after planting in soil was affected by their exposure time. This effect differed between stands, but a short germination time did not explain a better survival of some stands. These results show that achenes may differ in their dispersal potential in terms of floatability, as well as tolerance of seedlings to water exposure during dispersal. This study also highlights the fact that achenes of some stands present a combination of traits particularly adapted to long distance dispersal through watercourses, which can contribute to the extension of the invaded area.

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“…narrow and deep openchannel flows in the literature, as shown, for instance byRendu et al (2017) with b/h~1.1 orBonakdari et al (2008) with b/h~1.8. Unfortunately, the ADV is not able to measure the details of the velocity profiles in the near-bed region to highlight the transitions between viscous, elastic (with additives) and logarithmic sub-layers.…”

mentioning

confidence: 99%

Smoother Than Smooth: Increasing the Flow Conveyance of an Open-Channel Flow by Using Drag Reduction Methods

et al. 2019

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The drag reduction method by polymer additives is a common strategy used to minimize friction losses when carrying fluids (water, oil, slurries) in pipes over long distances. Previous studies showed that the interactions between the polymer and the turbulent structures of the flow tend to modify the streamwise velocity profile close to the walls by adding a so-called elastic sublayer between the classical viscous and log layers. The gain in linear head losses can reach up to 80%, depending on the roughness of the walls and the concentration of polymers. The application of this technique to sewers and the subsequent gain in discharge capacity motivated this work to quantitatively measure the drag reduction in classical open-channel flows. Three measurement campaigns were performed in a dedicated long flume for several water discharges and several polymer concentrations: backwater curves over smooth and rough channel walls (including velocity and turbulent shear stress profiles) and flows around emerging obstacles. The addition of polymers, even in limited concentrations, allowed a high friction decrease with a typical Darcy-Weisbach coefficient reduced by factors of 2 and 1.5, respectively in smooth and rough walls configurations without obstacles; but without strong modifications of the non-dimensional velocity profiles. Oppositely, when adding emerging obstacles,

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Laboratory investigation of Fallopia × bohemica fruits dispersal by watercourses

Cited by 4 publications

References 19 publications

Reducing Darcy coefficient by using drag reduction methods in open-channel flows: Effect on discharge capacity and potential application to mitigate river flooding impact

Reducing Darcy coefficient by using drag reduction methods in open-channel flows: Effect on discharge capacity and potential application to mitigate river flooding impact

Achene traits involved in the water dispersal of the invasive Fallopia × bohemica complex: Variability and dispersal strategies

Smoother Than Smooth: Increasing the Flow Conveyance of an Open-Channel Flow by Using Drag Reduction Methods

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