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Modelling of Beach State Variability / BLESSING NWANOSIKE

Swansea University Author: BLESSING NWANOSIKE

  • E-Thesis under embargo until: 13th December 2024

DOI (Published version): 10.23889/SUThesis.67184

Abstract

Beaches change their shape in response to the incoming wave conditions. They may exhibit changes both in their longshore configuration and their cross-section. Beach cross-sections have been classified into different categories, broadly corresponding to different states that represent different bala...

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Published: Swansea University, Wales, UK 2024
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
Supervisor: Karunarathna, H., & Reeve, D.
URI: https://cronfa.swan.ac.uk/Record/cronfa67184
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In this approach, beach evolution over time can be considered as a sequence of changes between different beach states. It is important to forecast impending morphodynamic states of a given beach. The main goal of this thesis focuses on deriving an empirical relationship between different beach states and incident wave conditions, using synthetic beach state simulations from a numerical coastal model, which would provide coastal managers with a simple and effective means of predicting how beaches will evolve over different timescales and therefore assist with the management of the beach. To create a database from which an empirical beach state variability model was developed, a process-based morphodynamic numerical model (XBeach :1D) was employed to generate different beach profiles based on over 300 wave simulations. The XBeach model was validated against a set of large-scale experimental data in order to develop a practical empirical model for evaluating different beach states. This numerical model was able to simulate morphodynamic changes of beaches with widely varying sediment characteristics and slopes from a large number of incident wave conditions. Different parameters were examined, but particular focus was put on describing the response of the nearshore berm formation and shoreline change with respect to the beach states. Hence, the Dean parameter, was used to represent the beach state. Berm crest, berm height, berm length and shoreline change were extracted from the numerical simulations. An empirical formulation was derived to predict each of these parameters, thus determining the beach state variability for incident wave conditions. The formulation takes into account several factors, such as water depth, wave steepness, the slope of the beach, and a derived parameter from the data, which can all contribute to determining beach state variability.The empirical formulation was also validated against beach profile change at a number of field sites with a wide range of characteristics (Narrabeen Beach, NSW, Australia, Hasaki Beach, Japan, Duck Beach, NC,United States, and an experimental data by Andrea Polidoro). The validation was based on selected storm profile on each field analysed. In most cases, the empirical model captured underwater berm development satisfactorily, but shoreline change was not adequately captured. As a result of these findings, the results demonstrate that the shape of the antecedent beach profile is crucial, as all parameters are calculated based on the profile. Thus, the empirical model functions better for intermediate to dissipative beaches, whereas it underestimates all quantities for highly dissipative beaches. The model’s performance is particularly notable in accurately predicting various parameters for these types of beaches, enhancing our understanding of the complex interplay between beach states and wave conditions. Despite limitations, the model’s practical implications are noteworthy for coastal management. It offers a valuable tool for informing strategies such as infrastructure planning. Additionally, its applicability to different coastal systems holds promise for broader insights into coastal morphodynamics, benefiting coastal communities globally. The empirical model will enhance understanding of the relationship between beach state and wave conditions, facilitating more effective coastal management and decision-making processes.</abstract><type>E-Thesis</type><journal/><volume/><journalNumber/><paginationStart/><paginationEnd/><publisher/><placeOfPublication>Swansea University, Wales, UK</placeOfPublication><isbnPrint/><isbnElectronic/><issnPrint/><issnElectronic/><keywords>Empirical formulation, XBeach, Dean’s parameter, Nearshore morphodynamics, Beach profile, Berm formation, Shoreline change, Water level variation.</keywords><publishedDay>13</publishedDay><publishedMonth>5</publishedMonth><publishedYear>2024</publishedYear><publishedDate>2024-05-13</publishedDate><doi>10.23889/SUThesis.67184</doi><url/><notes>A selection of content is redacted or is partially redacted from this thesis to protect sensitive and personal information.</notes><college>COLLEGE NANME</college><CollegeCode>COLLEGE CODE</CollegeCode><institution>Swansea University</institution><supervisor>Karunarathna, H., &amp; Reeve, D.</supervisor><degreelevel>Doctoral</degreelevel><degreename>Ph.D</degreename><degreesponsorsfunders>Petroleum Technology Development Fund Nigeria</degreesponsorsfunders><apcterm/><funders>Petroleum Technology Development Fund Nigeria</funders><projectreference/><lastEdited>2024-07-25T13:11:55.7404496</lastEdited><Created>2024-07-25T12:54:14.5058116</Created><path><level id="1">Faculty of Science and Engineering</level><level id="2">School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Civil Engineering</level></path><authors><author><firstname>BLESSING</firstname><surname>NWANOSIKE</surname><order>1</order></author></authors><documents><document><filename>Under embargo</filename><originalFilename>Under embargo</originalFilename><uploaded>2024-07-25T13:04:56.5532911</uploaded><type>Output</type><contentLength>5786574</contentLength><contentType>application/pdf</contentType><version>E-Thesis</version><cronfaStatus>true</cronfaStatus><embargoDate>2024-12-13T00:00:00.0000000</embargoDate><documentNotes>Copyright: The Author, Blessing Chinasa Nwanosike, 2023 Distributed under the terms of a Creative Commons Attribution 4.0 License (CC BY 4.0)</documentNotes><copyrightCorrect>true</copyrightCorrect><language>eng</language><licence>https://creativecommons.org/licenses/by/4.0/</licence></document></documents><OutputDurs/></rfc1807>
spelling v2 67184 2024-07-25 Modelling of Beach State Variability 11f136428ee7b99247d9885250fa6030 BLESSING NWANOSIKE BLESSING NWANOSIKE true false 2024-07-25 Beaches change their shape in response to the incoming wave conditions. They may exhibit changes both in their longshore configuration and their cross-section. Beach cross-sections have been classified into different categories, broadly corresponding to different states that represent different balances between the physical forces arising between the waves, currents, and sediments. In this approach, beach evolution over time can be considered as a sequence of changes between different beach states. It is important to forecast impending morphodynamic states of a given beach. The main goal of this thesis focuses on deriving an empirical relationship between different beach states and incident wave conditions, using synthetic beach state simulations from a numerical coastal model, which would provide coastal managers with a simple and effective means of predicting how beaches will evolve over different timescales and therefore assist with the management of the beach. To create a database from which an empirical beach state variability model was developed, a process-based morphodynamic numerical model (XBeach :1D) was employed to generate different beach profiles based on over 300 wave simulations. The XBeach model was validated against a set of large-scale experimental data in order to develop a practical empirical model for evaluating different beach states. This numerical model was able to simulate morphodynamic changes of beaches with widely varying sediment characteristics and slopes from a large number of incident wave conditions. Different parameters were examined, but particular focus was put on describing the response of the nearshore berm formation and shoreline change with respect to the beach states. Hence, the Dean parameter, was used to represent the beach state. Berm crest, berm height, berm length and shoreline change were extracted from the numerical simulations. An empirical formulation was derived to predict each of these parameters, thus determining the beach state variability for incident wave conditions. The formulation takes into account several factors, such as water depth, wave steepness, the slope of the beach, and a derived parameter from the data, which can all contribute to determining beach state variability.The empirical formulation was also validated against beach profile change at a number of field sites with a wide range of characteristics (Narrabeen Beach, NSW, Australia, Hasaki Beach, Japan, Duck Beach, NC,United States, and an experimental data by Andrea Polidoro). The validation was based on selected storm profile on each field analysed. In most cases, the empirical model captured underwater berm development satisfactorily, but shoreline change was not adequately captured. As a result of these findings, the results demonstrate that the shape of the antecedent beach profile is crucial, as all parameters are calculated based on the profile. Thus, the empirical model functions better for intermediate to dissipative beaches, whereas it underestimates all quantities for highly dissipative beaches. The model’s performance is particularly notable in accurately predicting various parameters for these types of beaches, enhancing our understanding of the complex interplay between beach states and wave conditions. Despite limitations, the model’s practical implications are noteworthy for coastal management. It offers a valuable tool for informing strategies such as infrastructure planning. Additionally, its applicability to different coastal systems holds promise for broader insights into coastal morphodynamics, benefiting coastal communities globally. The empirical model will enhance understanding of the relationship between beach state and wave conditions, facilitating more effective coastal management and decision-making processes. E-Thesis Swansea University, Wales, UK Empirical formulation, XBeach, Dean’s parameter, Nearshore morphodynamics, Beach profile, Berm formation, Shoreline change, Water level variation. 13 5 2024 2024-05-13 10.23889/SUThesis.67184 A selection of content is redacted or is partially redacted from this thesis to protect sensitive and personal information. COLLEGE NANME COLLEGE CODE Swansea University Karunarathna, H., & Reeve, D. Doctoral Ph.D Petroleum Technology Development Fund Nigeria Petroleum Technology Development Fund Nigeria 2024-07-25T13:11:55.7404496 2024-07-25T12:54:14.5058116 Faculty of Science and Engineering School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Civil Engineering BLESSING NWANOSIKE 1 Under embargo Under embargo 2024-07-25T13:04:56.5532911 Output 5786574 application/pdf E-Thesis true 2024-12-13T00:00:00.0000000 Copyright: The Author, Blessing Chinasa Nwanosike, 2023 Distributed under the terms of a Creative Commons Attribution 4.0 License (CC BY 4.0) true eng https://creativecommons.org/licenses/by/4.0/
title Modelling of Beach State Variability
spellingShingle Modelling of Beach State Variability
BLESSING NWANOSIKE
title_short Modelling of Beach State Variability
title_full Modelling of Beach State Variability
title_fullStr Modelling of Beach State Variability
title_full_unstemmed Modelling of Beach State Variability
title_sort Modelling of Beach State Variability
author_id_str_mv 11f136428ee7b99247d9885250fa6030
author_id_fullname_str_mv 11f136428ee7b99247d9885250fa6030_***_BLESSING NWANOSIKE
author BLESSING NWANOSIKE
author2 BLESSING NWANOSIKE
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institution Swansea University
doi_str_mv 10.23889/SUThesis.67184
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hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Civil Engineering{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Civil Engineering
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description Beaches change their shape in response to the incoming wave conditions. They may exhibit changes both in their longshore configuration and their cross-section. Beach cross-sections have been classified into different categories, broadly corresponding to different states that represent different balances between the physical forces arising between the waves, currents, and sediments. In this approach, beach evolution over time can be considered as a sequence of changes between different beach states. It is important to forecast impending morphodynamic states of a given beach. The main goal of this thesis focuses on deriving an empirical relationship between different beach states and incident wave conditions, using synthetic beach state simulations from a numerical coastal model, which would provide coastal managers with a simple and effective means of predicting how beaches will evolve over different timescales and therefore assist with the management of the beach. To create a database from which an empirical beach state variability model was developed, a process-based morphodynamic numerical model (XBeach :1D) was employed to generate different beach profiles based on over 300 wave simulations. The XBeach model was validated against a set of large-scale experimental data in order to develop a practical empirical model for evaluating different beach states. This numerical model was able to simulate morphodynamic changes of beaches with widely varying sediment characteristics and slopes from a large number of incident wave conditions. Different parameters were examined, but particular focus was put on describing the response of the nearshore berm formation and shoreline change with respect to the beach states. Hence, the Dean parameter, was used to represent the beach state. Berm crest, berm height, berm length and shoreline change were extracted from the numerical simulations. An empirical formulation was derived to predict each of these parameters, thus determining the beach state variability for incident wave conditions. The formulation takes into account several factors, such as water depth, wave steepness, the slope of the beach, and a derived parameter from the data, which can all contribute to determining beach state variability.The empirical formulation was also validated against beach profile change at a number of field sites with a wide range of characteristics (Narrabeen Beach, NSW, Australia, Hasaki Beach, Japan, Duck Beach, NC,United States, and an experimental data by Andrea Polidoro). The validation was based on selected storm profile on each field analysed. In most cases, the empirical model captured underwater berm development satisfactorily, but shoreline change was not adequately captured. As a result of these findings, the results demonstrate that the shape of the antecedent beach profile is crucial, as all parameters are calculated based on the profile. Thus, the empirical model functions better for intermediate to dissipative beaches, whereas it underestimates all quantities for highly dissipative beaches. The model’s performance is particularly notable in accurately predicting various parameters for these types of beaches, enhancing our understanding of the complex interplay between beach states and wave conditions. Despite limitations, the model’s practical implications are noteworthy for coastal management. It offers a valuable tool for informing strategies such as infrastructure planning. Additionally, its applicability to different coastal systems holds promise for broader insights into coastal morphodynamics, benefiting coastal communities globally. The empirical model will enhance understanding of the relationship between beach state and wave conditions, facilitating more effective coastal management and decision-making processes.
published_date 2024-05-13T13:11:55Z
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score 11.028798

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