A cross-shore beach profile evolution model

Mantripathi Prabath Ravindra Jayaratne, Md Rezaur Rahman, Tomoya Shibayama

    Research output: Contribution to journalArticle

    4 Citations (Scopus)

    Abstract

    Developing an accurate and reliable time-averaged beach profile evolution model under storm and nonstorm conditions is a challenging task. Over the last few decades, a number of beach deformation models have been developed under limited experimental conditions and uncertainties, and sometimes they required a long computation time. It is quite evident that a large amount of wave, current, sediment and beach profile data is available today. The present study leads to the development of a simple two-dimensional beach profile evolution model with on-offshore sand bar formation under nonstorm and storm conditions based on the time-averaged suspended sediment concentration models of Jayaratne and Shibayama [Jayaratne, M. P. R. and Shibayama, T. [2007] "Suspended sediment concentration on beaches under three different mechanisms," Coastal Eng. J., JSCE 49(4), 357-392.] and Jayaratne et al. [Jayaratne, M. P. R., Sritharan, S. and Shibayama, T. [2011] "Examination of the suspended sediment concentration formulae using full-scale rippled bed and sheet flow data," Coastal Eng. J., JSCE 53(4), 451-489.]. These models were formulated for computing sediment concentration in and outside the surf zone under three different mechanisms: (1) suspension due to turbulent motion over sand ripples, (2) suspension from sheet flow layer and (3) suspension due to turbulent motion under breaking waves. The suspended load is calculated by the product of time-averaged sediment concentration and undertow velocity from edge of the wave boundary layer to wave trough and mass transport velocity from wave trough to crest (bore-like wave region). Sediment transport in wave boundary layer is computed from the modified Watanabe [Watanabe, A. [1982] "Numerical model of nearshore currents and beach deformation model," Coastal Eng. Jpn., JSCE 25, 147-161.] model. Rattanapitikon and Shibayama [Rattanapitikon, W. and Shibayama, T. [1998] "Energy dissipation model for regular and irregular breaking waves," Coastal Eng. J., JSCE 40(4), 327-346.] wave model is used to calculate the average rate of energy dissipation due to wave breaking. The beach deformation is calculated from the conservation of sediment mass while the avalanching concept of Larson and Kraus [Larson, M. and Kraus, N. C. [1989] SBEACH: Numerical model for simulating storm induced beach change, Report 1, Technical Report CERC-89-9, US Army Eng. Water. Exp. Station.] is used to re-distribute the sediment mass in neighboring grids for a steady solution. Published field-scale experimental and natural beach profiles from five high-quality data sources from 1983-2009 [Kajima et al., 1983; Kraus and Larson, 1988; Port and Airport Research Institute, Japan, 2005, 2009; Hasan and Takewaka, 2007, 2009; Ruessink et al., 2007] are used to verify the performance of the proposed numerical model. The key feature in this process-based model is that it takes about a couple of minutes to simulate beach profiles of a 2-3 days storm qualitatively at a fairly satisfactory level using a standard personal computer. It is found that the present numerical predictions are not better than the null hypothesis as the model is in a stage of ongoing development. Therefore, it is believed that the final model is often of more value to a practical coastal engineer than a very detailed study of hydrodynamics and sediment transport study, however an incorporation of swash dynamics, more precise evaluation of offshore sand bar formation and continuation to a longer time scale with precise beach deformation are recommended as the next stage of the model.

    Original languageEnglish
    Article number1450020
    JournalCoastal Engineering Journal
    Volume56
    Issue number4
    DOIs
    Publication statusPublished - 2014 Dec 16

    Fingerprint

    Beaches
    Sediment
    Sediments
    Suspended sediments
    Model
    Breaking Waves
    Sediment Transport
    Numerical models
    Sand
    Sediment transport
    Energy Dissipation
    Profile
    Boundary Layer
    Energy dissipation
    Boundary layers
    Wave Breaking
    Mass Transport
    Motion
    Data Quality
    Ripple

    Keywords

    • avalanching concept
    • average rate of energy dissipation
    • conservation of sediment mass
    • field-scale experimental and natural beach profile data
    • on-offshore sand bar formation
    • practical coastal engineer
    • process-based model
    • standard personal computer
    • time-averaged suspended sediment concentration
    • Two-dimensional beach profile evolution model

    ASJC Scopus subject areas

    • Civil and Structural Engineering
    • Modelling and Simulation
    • Ocean Engineering

    Cite this

    A cross-shore beach profile evolution model. / Jayaratne, Mantripathi Prabath Ravindra; Rahman, Md Rezaur; Shibayama, Tomoya.

    In: Coastal Engineering Journal, Vol. 56, No. 4, 1450020, 16.12.2014.

    Research output: Contribution to journalArticle

    Jayaratne, Mantripathi Prabath Ravindra ; Rahman, Md Rezaur ; Shibayama, Tomoya. / A cross-shore beach profile evolution model. In: Coastal Engineering Journal. 2014 ; Vol. 56, No. 4.
    @article{9ab750a76730494c90b2f550c923200e,
    title = "A cross-shore beach profile evolution model",
    abstract = "Developing an accurate and reliable time-averaged beach profile evolution model under storm and nonstorm conditions is a challenging task. Over the last few decades, a number of beach deformation models have been developed under limited experimental conditions and uncertainties, and sometimes they required a long computation time. It is quite evident that a large amount of wave, current, sediment and beach profile data is available today. The present study leads to the development of a simple two-dimensional beach profile evolution model with on-offshore sand bar formation under nonstorm and storm conditions based on the time-averaged suspended sediment concentration models of Jayaratne and Shibayama [Jayaratne, M. P. R. and Shibayama, T. [2007] {"}Suspended sediment concentration on beaches under three different mechanisms,{"} Coastal Eng. J., JSCE 49(4), 357-392.] and Jayaratne et al. [Jayaratne, M. P. R., Sritharan, S. and Shibayama, T. [2011] {"}Examination of the suspended sediment concentration formulae using full-scale rippled bed and sheet flow data,{"} Coastal Eng. J., JSCE 53(4), 451-489.]. These models were formulated for computing sediment concentration in and outside the surf zone under three different mechanisms: (1) suspension due to turbulent motion over sand ripples, (2) suspension from sheet flow layer and (3) suspension due to turbulent motion under breaking waves. The suspended load is calculated by the product of time-averaged sediment concentration and undertow velocity from edge of the wave boundary layer to wave trough and mass transport velocity from wave trough to crest (bore-like wave region). Sediment transport in wave boundary layer is computed from the modified Watanabe [Watanabe, A. [1982] {"}Numerical model of nearshore currents and beach deformation model,{"} Coastal Eng. Jpn., JSCE 25, 147-161.] model. Rattanapitikon and Shibayama [Rattanapitikon, W. and Shibayama, T. [1998] {"}Energy dissipation model for regular and irregular breaking waves,{"} Coastal Eng. J., JSCE 40(4), 327-346.] wave model is used to calculate the average rate of energy dissipation due to wave breaking. The beach deformation is calculated from the conservation of sediment mass while the avalanching concept of Larson and Kraus [Larson, M. and Kraus, N. C. [1989] SBEACH: Numerical model for simulating storm induced beach change, Report 1, Technical Report CERC-89-9, US Army Eng. Water. Exp. Station.] is used to re-distribute the sediment mass in neighboring grids for a steady solution. Published field-scale experimental and natural beach profiles from five high-quality data sources from 1983-2009 [Kajima et al., 1983; Kraus and Larson, 1988; Port and Airport Research Institute, Japan, 2005, 2009; Hasan and Takewaka, 2007, 2009; Ruessink et al., 2007] are used to verify the performance of the proposed numerical model. The key feature in this process-based model is that it takes about a couple of minutes to simulate beach profiles of a 2-3 days storm qualitatively at a fairly satisfactory level using a standard personal computer. It is found that the present numerical predictions are not better than the null hypothesis as the model is in a stage of ongoing development. Therefore, it is believed that the final model is often of more value to a practical coastal engineer than a very detailed study of hydrodynamics and sediment transport study, however an incorporation of swash dynamics, more precise evaluation of offshore sand bar formation and continuation to a longer time scale with precise beach deformation are recommended as the next stage of the model.",
    keywords = "avalanching concept, average rate of energy dissipation, conservation of sediment mass, field-scale experimental and natural beach profile data, on-offshore sand bar formation, practical coastal engineer, process-based model, standard personal computer, time-averaged suspended sediment concentration, Two-dimensional beach profile evolution model",
    author = "Jayaratne, {Mantripathi Prabath Ravindra} and Rahman, {Md Rezaur} and Tomoya Shibayama",
    year = "2014",
    month = "12",
    day = "16",
    doi = "10.1142/S057856341450020X",
    language = "English",
    volume = "56",
    journal = "Coastal Engineering in Japan",
    issn = "0578-5634",
    publisher = "World Scientific Publishing Co. Pte Ltd",
    number = "4",

    }

    TY - JOUR

    T1 - A cross-shore beach profile evolution model

    AU - Jayaratne, Mantripathi Prabath Ravindra

    AU - Rahman, Md Rezaur

    AU - Shibayama, Tomoya

    PY - 2014/12/16

    Y1 - 2014/12/16

    N2 - Developing an accurate and reliable time-averaged beach profile evolution model under storm and nonstorm conditions is a challenging task. Over the last few decades, a number of beach deformation models have been developed under limited experimental conditions and uncertainties, and sometimes they required a long computation time. It is quite evident that a large amount of wave, current, sediment and beach profile data is available today. The present study leads to the development of a simple two-dimensional beach profile evolution model with on-offshore sand bar formation under nonstorm and storm conditions based on the time-averaged suspended sediment concentration models of Jayaratne and Shibayama [Jayaratne, M. P. R. and Shibayama, T. [2007] "Suspended sediment concentration on beaches under three different mechanisms," Coastal Eng. J., JSCE 49(4), 357-392.] and Jayaratne et al. [Jayaratne, M. P. R., Sritharan, S. and Shibayama, T. [2011] "Examination of the suspended sediment concentration formulae using full-scale rippled bed and sheet flow data," Coastal Eng. J., JSCE 53(4), 451-489.]. These models were formulated for computing sediment concentration in and outside the surf zone under three different mechanisms: (1) suspension due to turbulent motion over sand ripples, (2) suspension from sheet flow layer and (3) suspension due to turbulent motion under breaking waves. The suspended load is calculated by the product of time-averaged sediment concentration and undertow velocity from edge of the wave boundary layer to wave trough and mass transport velocity from wave trough to crest (bore-like wave region). Sediment transport in wave boundary layer is computed from the modified Watanabe [Watanabe, A. [1982] "Numerical model of nearshore currents and beach deformation model," Coastal Eng. Jpn., JSCE 25, 147-161.] model. Rattanapitikon and Shibayama [Rattanapitikon, W. and Shibayama, T. [1998] "Energy dissipation model for regular and irregular breaking waves," Coastal Eng. J., JSCE 40(4), 327-346.] wave model is used to calculate the average rate of energy dissipation due to wave breaking. The beach deformation is calculated from the conservation of sediment mass while the avalanching concept of Larson and Kraus [Larson, M. and Kraus, N. C. [1989] SBEACH: Numerical model for simulating storm induced beach change, Report 1, Technical Report CERC-89-9, US Army Eng. Water. Exp. Station.] is used to re-distribute the sediment mass in neighboring grids for a steady solution. Published field-scale experimental and natural beach profiles from five high-quality data sources from 1983-2009 [Kajima et al., 1983; Kraus and Larson, 1988; Port and Airport Research Institute, Japan, 2005, 2009; Hasan and Takewaka, 2007, 2009; Ruessink et al., 2007] are used to verify the performance of the proposed numerical model. The key feature in this process-based model is that it takes about a couple of minutes to simulate beach profiles of a 2-3 days storm qualitatively at a fairly satisfactory level using a standard personal computer. It is found that the present numerical predictions are not better than the null hypothesis as the model is in a stage of ongoing development. Therefore, it is believed that the final model is often of more value to a practical coastal engineer than a very detailed study of hydrodynamics and sediment transport study, however an incorporation of swash dynamics, more precise evaluation of offshore sand bar formation and continuation to a longer time scale with precise beach deformation are recommended as the next stage of the model.

    AB - Developing an accurate and reliable time-averaged beach profile evolution model under storm and nonstorm conditions is a challenging task. Over the last few decades, a number of beach deformation models have been developed under limited experimental conditions and uncertainties, and sometimes they required a long computation time. It is quite evident that a large amount of wave, current, sediment and beach profile data is available today. The present study leads to the development of a simple two-dimensional beach profile evolution model with on-offshore sand bar formation under nonstorm and storm conditions based on the time-averaged suspended sediment concentration models of Jayaratne and Shibayama [Jayaratne, M. P. R. and Shibayama, T. [2007] "Suspended sediment concentration on beaches under three different mechanisms," Coastal Eng. J., JSCE 49(4), 357-392.] and Jayaratne et al. [Jayaratne, M. P. R., Sritharan, S. and Shibayama, T. [2011] "Examination of the suspended sediment concentration formulae using full-scale rippled bed and sheet flow data," Coastal Eng. J., JSCE 53(4), 451-489.]. These models were formulated for computing sediment concentration in and outside the surf zone under three different mechanisms: (1) suspension due to turbulent motion over sand ripples, (2) suspension from sheet flow layer and (3) suspension due to turbulent motion under breaking waves. The suspended load is calculated by the product of time-averaged sediment concentration and undertow velocity from edge of the wave boundary layer to wave trough and mass transport velocity from wave trough to crest (bore-like wave region). Sediment transport in wave boundary layer is computed from the modified Watanabe [Watanabe, A. [1982] "Numerical model of nearshore currents and beach deformation model," Coastal Eng. Jpn., JSCE 25, 147-161.] model. Rattanapitikon and Shibayama [Rattanapitikon, W. and Shibayama, T. [1998] "Energy dissipation model for regular and irregular breaking waves," Coastal Eng. J., JSCE 40(4), 327-346.] wave model is used to calculate the average rate of energy dissipation due to wave breaking. The beach deformation is calculated from the conservation of sediment mass while the avalanching concept of Larson and Kraus [Larson, M. and Kraus, N. C. [1989] SBEACH: Numerical model for simulating storm induced beach change, Report 1, Technical Report CERC-89-9, US Army Eng. Water. Exp. Station.] is used to re-distribute the sediment mass in neighboring grids for a steady solution. Published field-scale experimental and natural beach profiles from five high-quality data sources from 1983-2009 [Kajima et al., 1983; Kraus and Larson, 1988; Port and Airport Research Institute, Japan, 2005, 2009; Hasan and Takewaka, 2007, 2009; Ruessink et al., 2007] are used to verify the performance of the proposed numerical model. The key feature in this process-based model is that it takes about a couple of minutes to simulate beach profiles of a 2-3 days storm qualitatively at a fairly satisfactory level using a standard personal computer. It is found that the present numerical predictions are not better than the null hypothesis as the model is in a stage of ongoing development. Therefore, it is believed that the final model is often of more value to a practical coastal engineer than a very detailed study of hydrodynamics and sediment transport study, however an incorporation of swash dynamics, more precise evaluation of offshore sand bar formation and continuation to a longer time scale with precise beach deformation are recommended as the next stage of the model.

    KW - avalanching concept

    KW - average rate of energy dissipation

    KW - conservation of sediment mass

    KW - field-scale experimental and natural beach profile data

    KW - on-offshore sand bar formation

    KW - practical coastal engineer

    KW - process-based model

    KW - standard personal computer

    KW - time-averaged suspended sediment concentration

    KW - Two-dimensional beach profile evolution model

    UR - http://www.scopus.com/inward/record.url?scp=84929347186&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=84929347186&partnerID=8YFLogxK

    U2 - 10.1142/S057856341450020X

    DO - 10.1142/S057856341450020X

    M3 - Article

    AN - SCOPUS:84929347186

    VL - 56

    JO - Coastal Engineering in Japan

    JF - Coastal Engineering in Japan

    SN - 0578-5634

    IS - 4

    M1 - 1450020

    ER -