Sand size versus beachface slope — An explanation based on the Constructal Law
Autor(a) principal: | |
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Data de Publicação: | 2010 |
Outros Autores: | |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10174/4777 |
Resumo: | The relationship between beachface slope and sand grain size has been established based on multiple observations of beach characteristics in many parts of the world. We show that this observational result may be understood in the light of the Constructal Law (Bejan, 1997). A model of wave run-up and run-down along the beachface (swash) was developed to account for superficial flows together with flows through the porous sand bed of average porosity 0.35, the permeability of which may be related to grain diameter and sphericity (0.9 for sand grains) through the Kozeny–Carmán equation. Then, by using the Constructal Law, we minimized the time for completing a swash cycle, under fixed wave height and sand grain diameter. As the result, a relationship involving sand grain size, beachface slope and open ocean wave height has been obtained, and then discussed and validated against experimental data. In addition, this relationship has also been used to illuminate beachface dynamic processes, namely the reshaping of sandy beachfaces in response to changes in wave height. Though the model used in this work may be improved further, the results appear to show, as with other natural systems, that beachface morphing in time may be understood based on a unifying principle — the Constructal Law. |
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7160 |
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Sand size versus beachface slope — An explanation based on the Constructal LawBeachface dynamicsSediment sizeBeach slopeConstructal LawThe relationship between beachface slope and sand grain size has been established based on multiple observations of beach characteristics in many parts of the world. We show that this observational result may be understood in the light of the Constructal Law (Bejan, 1997). A model of wave run-up and run-down along the beachface (swash) was developed to account for superficial flows together with flows through the porous sand bed of average porosity 0.35, the permeability of which may be related to grain diameter and sphericity (0.9 for sand grains) through the Kozeny–Carmán equation. Then, by using the Constructal Law, we minimized the time for completing a swash cycle, under fixed wave height and sand grain diameter. As the result, a relationship involving sand grain size, beachface slope and open ocean wave height has been obtained, and then discussed and validated against experimental data. In addition, this relationship has also been used to illuminate beachface dynamic processes, namely the reshaping of sandy beachfaces in response to changes in wave height. Though the model used in this work may be improved further, the results appear to show, as with other natural systems, that beachface morphing in time may be understood based on a unifying principle — the Constructal Law.Elsevier2012-01-31T14:30:18Z2012-01-312010-01-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://hdl.handle.net/10174/4777http://hdl.handle.net/10174/4777engGeomorphology 114 (2010) 276–283ahr@uevora.ptcgama@uevora.pt250Reis, António HeitorGama, Cristinainfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2024-01-03T18:42:50Zoai:dspace.uevora.pt:10174/4777Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T00:59:52.269101Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Sand size versus beachface slope — An explanation based on the Constructal Law |
title |
Sand size versus beachface slope — An explanation based on the Constructal Law |
spellingShingle |
Sand size versus beachface slope — An explanation based on the Constructal Law Reis, António Heitor Beachface dynamics Sediment size Beach slope Constructal Law |
title_short |
Sand size versus beachface slope — An explanation based on the Constructal Law |
title_full |
Sand size versus beachface slope — An explanation based on the Constructal Law |
title_fullStr |
Sand size versus beachface slope — An explanation based on the Constructal Law |
title_full_unstemmed |
Sand size versus beachface slope — An explanation based on the Constructal Law |
title_sort |
Sand size versus beachface slope — An explanation based on the Constructal Law |
author |
Reis, António Heitor |
author_facet |
Reis, António Heitor Gama, Cristina |
author_role |
author |
author2 |
Gama, Cristina |
author2_role |
author |
dc.contributor.author.fl_str_mv |
Reis, António Heitor Gama, Cristina |
dc.subject.por.fl_str_mv |
Beachface dynamics Sediment size Beach slope Constructal Law |
topic |
Beachface dynamics Sediment size Beach slope Constructal Law |
description |
The relationship between beachface slope and sand grain size has been established based on multiple observations of beach characteristics in many parts of the world. We show that this observational result may be understood in the light of the Constructal Law (Bejan, 1997). A model of wave run-up and run-down along the beachface (swash) was developed to account for superficial flows together with flows through the porous sand bed of average porosity 0.35, the permeability of which may be related to grain diameter and sphericity (0.9 for sand grains) through the Kozeny–Carmán equation. Then, by using the Constructal Law, we minimized the time for completing a swash cycle, under fixed wave height and sand grain diameter. As the result, a relationship involving sand grain size, beachface slope and open ocean wave height has been obtained, and then discussed and validated against experimental data. In addition, this relationship has also been used to illuminate beachface dynamic processes, namely the reshaping of sandy beachfaces in response to changes in wave height. Though the model used in this work may be improved further, the results appear to show, as with other natural systems, that beachface morphing in time may be understood based on a unifying principle — the Constructal Law. |
publishDate |
2010 |
dc.date.none.fl_str_mv |
2010-01-01T00:00:00Z 2012-01-31T14:30:18Z 2012-01-31 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10174/4777 http://hdl.handle.net/10174/4777 |
url |
http://hdl.handle.net/10174/4777 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Geomorphology 114 (2010) 276–283 ahr@uevora.pt cgama@uevora.pt 250 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.publisher.none.fl_str_mv |
Elsevier |
publisher.none.fl_str_mv |
Elsevier |
dc.source.none.fl_str_mv |
reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
instname_str |
Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
instacron_str |
RCAAP |
institution |
RCAAP |
reponame_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
collection |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
repository.name.fl_str_mv |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
repository.mail.fl_str_mv |
|
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1799136481577533440 |