Evaluation of local turbulent support of particles in intense transport of contact load

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21110%2F19%3A00334021" target="_blank" >RIV/68407700:21110/19:00334021 - isvavai.cz</a>

Výsledek na webu

—

DOI - Digital Object Identifier

—

Jazyk výsledku

angličtina

Název v původním jazyce

Evaluation of local turbulent support of particles in intense transport of contact load

Popis výsledku v původním jazyce

Intense transport of colliding solid grains in sheet flow (open-channel steady uniform turbulent flow at high bed shear) is evaluated using experimentally and theoretically determined distributions of governing flow quantities. The experimental distributions include results of measurements of granular concentration and velocity across sheet flow above an eroded bed in a laboratory tilting flume. Two fractions of lightweight model sediment (plastic grains) were tested within a broad range of flow conditions in the upper plane bed regime. Momentum equations and constitutive relations of the kinetic theory of granular flows were employed to derive distributions of granular and liquid stresses across the flow from the measured distributions of concentration and velocity. Hence the conditions were set for an evaluation of the ability of the flow of the carrying liquid to locally support transported sediment particles by the diffusive action of carrier turbulent eddies. Local values of the carrier shear velocity and particle settling velocity are mutually compared in order to evaluate the ability of the local turbulent support. The results indicate that the chance for the turbulent support (as additional mechanism to collisional support) does not vary significantly in the core of the collisional layer developed in the sheet flow while it tends to disappear in the lowest part of the flow depth if the long-term intergranular contacts associated with high local concentration of grains dominate the particle support.

Název v anglickém jazyce

Evaluation of local turbulent support of particles in intense transport of contact load

Popis výsledku anglicky

Intense transport of colliding solid grains in sheet flow (open-channel steady uniform turbulent flow at high bed shear) is evaluated using experimentally and theoretically determined distributions of governing flow quantities. The experimental distributions include results of measurements of granular concentration and velocity across sheet flow above an eroded bed in a laboratory tilting flume. Two fractions of lightweight model sediment (plastic grains) were tested within a broad range of flow conditions in the upper plane bed regime. Momentum equations and constitutive relations of the kinetic theory of granular flows were employed to derive distributions of granular and liquid stresses across the flow from the measured distributions of concentration and velocity. Hence the conditions were set for an evaluation of the ability of the flow of the carrying liquid to locally support transported sediment particles by the diffusive action of carrier turbulent eddies. Local values of the carrier shear velocity and particle settling velocity are mutually compared in order to evaluate the ability of the local turbulent support. The results indicate that the chance for the turbulent support (as additional mechanism to collisional support) does not vary significantly in the core of the collisional layer developed in the sheet flow while it tends to disappear in the lowest part of the flow depth if the long-term intergranular contacts associated with high local concentration of grains dominate the particle support.

Druh

D - Stať ve sborníku

CEP obor

—

OECD FORD obor

20101 - Civil engineering

Projekt

<a href="/cs/project/GA19-18411S" target="_blank" >GA19-18411S: Modelování intenzivního chodu směsi dnových a nesených splavenin</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2019

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

Proc. 19th Int. Conference on Transport & Sedimentation of Solid Particles

ISBN

—

ISSN

0867-7964

e-ISSN

—

Počet stran výsledku

8

Strana od-do

31-38

Název nakladatele

Wroclaw University of Environmental And Life Sciences

Místo vydání

Wroclaw

Místo konání akce

Cape Town

Datum konání akce

24. 9. 2019

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

—