MODELLING OF COLLISIONAL BED LOAD AT HIGH BED SHEAR

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21110%2F18%3A00323772" target="_blank" >RIV/68407700:21110/18:00323772 - isvavai.cz</a>

Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

MODELLING OF COLLISIONAL BED LOAD AT HIGH BED SHEAR

Popis výsledku v původním jazyce

Sediment-laden turbulent flow at high bed shear in an open channel with a mobile bed is discussed. The bed surface is plane, fully mobilized (bed Shields parameter between 0.4 and 2.0 approximately) and interacts with a developed transport layer in which transported sediment grains are supported by mutual collisions. The transport layer occupies a considerable part of the flow depth. The distribution of grains across the transport layer exhibits a steep gradient of local granular volumetric concentration between the top of the layer (the local concentration is virtually zero) and the bottom of the layer (the local concentration approaches the bed concentration). This affects behavior of flow carrying the collisional load. A granular-rheology based modeling approach is presented which enables to predict the collisional bed-load flow rate and other relevant parameters of a layered structure of the sediment-laden flow. The approach employs granular constitutive relations and conditions at layer interfaces to mutually relate the flow slope, depth, the thickness of the layers and flow rates of both the sediment and sediment-water mixture. Model predictions are compared with experimental results obtained for lightweight granular materials in a laboratory tilting flume. The experimental results include detailed profiles of the longitudinal velocity. Corresponding concentration profiles are derived from the measured velocity distribution, sediment flow rate and thickness of the collisional layer.

Název v anglickém jazyce

MODELLING OF COLLISIONAL BED LOAD AT HIGH BED SHEAR

Popis výsledku anglicky

Sediment-laden turbulent flow at high bed shear in an open channel with a mobile bed is discussed. The bed surface is plane, fully mobilized (bed Shields parameter between 0.4 and 2.0 approximately) and interacts with a developed transport layer in which transported sediment grains are supported by mutual collisions. The transport layer occupies a considerable part of the flow depth. The distribution of grains across the transport layer exhibits a steep gradient of local granular volumetric concentration between the top of the layer (the local concentration is virtually zero) and the bottom of the layer (the local concentration approaches the bed concentration). This affects behavior of flow carrying the collisional load. A granular-rheology based modeling approach is presented which enables to predict the collisional bed-load flow rate and other relevant parameters of a layered structure of the sediment-laden flow. The approach employs granular constitutive relations and conditions at layer interfaces to mutually relate the flow slope, depth, the thickness of the layers and flow rates of both the sediment and sediment-water mixture. Model predictions are compared with experimental results obtained for lightweight granular materials in a laboratory tilting flume. The experimental results include detailed profiles of the longitudinal velocity. Corresponding concentration profiles are derived from the measured velocity distribution, sediment flow rate and thickness of the collisional layer.

Druh

O - Ostatní výsledky

CEP obor

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OECD FORD obor

20101 - Civil engineering

Projekt

<a href="/cs/project/GA16-21421S" target="_blank" >GA16-21421S: Analýza stratifikovaného proudění s volnou hladinou založená na kinetické teorii zrnitých směsí</a><br>

Návaznosti

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

Rok uplatnění

2018

Kód důvěrnosti údajů

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