Celle circolari e reti di clasti in letti fluviali a sedimenti grossolani. Alcuni risultati sperimentali
Circle cells and clast networks in gravel-bed rivers. Some experimental results. - Extensive field work, begun in 1995, in highly diverse morphoclimatic environments (Northern England, Iceland, Italy, Southern Africa, Southern Australia and Antarctica) has shown the presence, in gravel-bed rivers, o...
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ftunicagliariris:oai:iris.unica.it:11584/34096 2024-01-28T10:00:36+01:00 Celle circolari e reti di clasti in letti fluviali a sedimenti grossolani. Alcuni risultati sperimentali CAU, LUCIANO BIAGINI E. Cau, Luciano Biagini, E. 2008 http://hdl.handle.net/11584/34096 ita ita volume:115 (2) firstpage:181 lastpage:200 numberofpages:20 journal:RIVISTA GEOGRAFICA ITALIANA http://hdl.handle.net/11584/34096 Clast cell Riverbed info:eu-repo/semantics/article 2008 ftunicagliariris 2024-01-03T17:47:15Z Circle cells and clast networks in gravel-bed rivers. Some experimental results. - Extensive field work, begun in 1995, in highly diverse morphoclimatic environments (Northern England, Iceland, Italy, Southern Africa, Southern Australia and Antarctica) has shown the presence, in gravel-bed rivers, of widespread clast cells, covering sometimes 50% or more of river bar areas. In order to reproduce the same processes in controlled conditions, a large number of flume experiments was carried out from 2003 onwards. We have been able to pinpoint two processes: an alluvial process with a trident-shaped flow which bifurcates in correspondence to the keystone, especially at the thalweg, and a random colluvial process whereby cells formed by bank landslides are exhumed by removal of fines at sub-critical flow rates. A dependence of flow patterns from keystone size has been demonstrated. Clast networks exercise a considerable sheltering effect against bed mobilization, as the network elements tend to dampen the energy of the flow. Similar networks are found in many other natural phenomena, suggesting the existence of an underlying order in nature. Article in Journal/Newspaper Antarc* Antarctica Iceland Università degli Studi di Cagliari: UNICA IRIS Trident ENVELOPE(169.233,169.233,-72.433,-72.433) |
institution |
Open Polar |
collection |
Università degli Studi di Cagliari: UNICA IRIS |
op_collection_id |
ftunicagliariris |
language |
Italian |
topic |
Clast cell Riverbed |
spellingShingle |
Clast cell Riverbed CAU, LUCIANO BIAGINI E. Celle circolari e reti di clasti in letti fluviali a sedimenti grossolani. Alcuni risultati sperimentali |
topic_facet |
Clast cell Riverbed |
description |
Circle cells and clast networks in gravel-bed rivers. Some experimental results. - Extensive field work, begun in 1995, in highly diverse morphoclimatic environments (Northern England, Iceland, Italy, Southern Africa, Southern Australia and Antarctica) has shown the presence, in gravel-bed rivers, of widespread clast cells, covering sometimes 50% or more of river bar areas. In order to reproduce the same processes in controlled conditions, a large number of flume experiments was carried out from 2003 onwards. We have been able to pinpoint two processes: an alluvial process with a trident-shaped flow which bifurcates in correspondence to the keystone, especially at the thalweg, and a random colluvial process whereby cells formed by bank landslides are exhumed by removal of fines at sub-critical flow rates. A dependence of flow patterns from keystone size has been demonstrated. Clast networks exercise a considerable sheltering effect against bed mobilization, as the network elements tend to dampen the energy of the flow. Similar networks are found in many other natural phenomena, suggesting the existence of an underlying order in nature. |
author2 |
Cau, Luciano Biagini, E. |
format |
Article in Journal/Newspaper |
author |
CAU, LUCIANO BIAGINI E. |
author_facet |
CAU, LUCIANO BIAGINI E. |
author_sort |
CAU, LUCIANO |
title |
Celle circolari e reti di clasti in letti fluviali a sedimenti grossolani. Alcuni risultati sperimentali |
title_short |
Celle circolari e reti di clasti in letti fluviali a sedimenti grossolani. Alcuni risultati sperimentali |
title_full |
Celle circolari e reti di clasti in letti fluviali a sedimenti grossolani. Alcuni risultati sperimentali |
title_fullStr |
Celle circolari e reti di clasti in letti fluviali a sedimenti grossolani. Alcuni risultati sperimentali |
title_full_unstemmed |
Celle circolari e reti di clasti in letti fluviali a sedimenti grossolani. Alcuni risultati sperimentali |
title_sort |
celle circolari e reti di clasti in letti fluviali a sedimenti grossolani. alcuni risultati sperimentali |
publishDate |
2008 |
url |
http://hdl.handle.net/11584/34096 |
long_lat |
ENVELOPE(169.233,169.233,-72.433,-72.433) |
geographic |
Trident |
geographic_facet |
Trident |
genre |
Antarc* Antarctica Iceland |
genre_facet |
Antarc* Antarctica Iceland |
op_relation |
volume:115 (2) firstpage:181 lastpage:200 numberofpages:20 journal:RIVISTA GEOGRAFICA ITALIANA http://hdl.handle.net/11584/34096 |
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1789325068191399936 |