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Fractional formula of sediment transport rate for graded sediment in wave-driven sheet flow
https://orcid.org/0000-0002-6244-7866
Abstract A fractional formula is proposed for graded sediment transport in wave-driven sheet flow. The formula considers phase lag, acceleration effect and asymmetric boundary layer development. The main parameters (erosion depth, boundary layer thickness, roughness height) are common for each fraction in the fractional formula. A fractional pseudo erosion depth is introduced to determine the individual sediment amount and concentration for different fractions. The formula includes a hiding-exposure factor of exposure height, which represents the selective transport of graded sediment and influences the phase lag. Two approaches (multiple fraction approach, MFA and grading curve approach, GCA) are applied to the formula to estimate total sediment transport rate. The graded sediment is sorted into specific fractions in the MFA, while divided into several equal fractions in the GCA. The formula is verified by instantaneous and net sediment transport rate data. The predictions of MFA and GCA are basically identical for instantaneous sediment transport rate and the overall accuracy is good. The gradation effect can increase or decrease the magnitude of instantaneous sediment transport rate, which depends on the behaviors and interactions of different fractions. Fractional net sediment transport rate is estimated by the formula with the MFA, which reasonably reproduces the onshore- or offshore-directed sediment transport for each fraction compared with existing formulae and numerical model. The performance of fraction number is discussed using the GCA. The proposed formula is capable of efficiently handling the graded sediment transport in wave-driven sheet flow.
Highlights Fractional formula is proposed for graded sediment transport in wave-driven sheet flow. Gradation effect is included through hiding-exposure factor of exposure height. Formula incorporates phase lag, acceleration effect and asymmetric boundary layer development. Two approaches (MFA and GCA) are employed to handle total sediment transport. Results reproduce promotion/inhibition and onshore/offshore sediment transport for each size fraction.
Fractional formula of sediment transport rate for graded sediment in wave-driven sheet flow
https://orcid.org/0000-0002-6244-7866
Abstract A fractional formula is proposed for graded sediment transport in wave-driven sheet flow. The formula considers phase lag, acceleration effect and asymmetric boundary layer development. The main parameters (erosion depth, boundary layer thickness, roughness height) are common for each fraction in the fractional formula. A fractional pseudo erosion depth is introduced to determine the individual sediment amount and concentration for different fractions. The formula includes a hiding-exposure factor of exposure height, which represents the selective transport of graded sediment and influences the phase lag. Two approaches (multiple fraction approach, MFA and grading curve approach, GCA) are applied to the formula to estimate total sediment transport rate. The graded sediment is sorted into specific fractions in the MFA, while divided into several equal fractions in the GCA. The formula is verified by instantaneous and net sediment transport rate data. The predictions of MFA and GCA are basically identical for instantaneous sediment transport rate and the overall accuracy is good. The gradation effect can increase or decrease the magnitude of instantaneous sediment transport rate, which depends on the behaviors and interactions of different fractions. Fractional net sediment transport rate is estimated by the formula with the MFA, which reasonably reproduces the onshore- or offshore-directed sediment transport for each fraction compared with existing formulae and numerical model. The performance of fraction number is discussed using the GCA. The proposed formula is capable of efficiently handling the graded sediment transport in wave-driven sheet flow.
Highlights Fractional formula is proposed for graded sediment transport in wave-driven sheet flow. Gradation effect is included through hiding-exposure factor of exposure height. Formula incorporates phase lag, acceleration effect and asymmetric boundary layer development. Two approaches (MFA and GCA) are employed to handle total sediment transport. Results reproduce promotion/inhibition and onshore/offshore sediment transport for each size fraction.
Fractional formula of sediment transport rate for graded sediment in wave-driven sheet flow
https://orcid.org/0000-0002-6244-7866
Abstract A fractional formula is proposed for graded sediment transport in wave-driven sheet flow. The formula considers phase lag, acceleration effect and asymmetric boundary layer development. The main parameters (erosion depth, boundary layer thickness, roughness height) are common for each fraction in the fractional formula. A fractional pseudo erosion depth is introduced to determine the individual sediment amount and concentration for different fractions. The formula includes a hiding-exposure factor of exposure height, which represents the selective transport of graded sediment and influences the phase lag. Two approaches (multiple fraction approach, MFA and grading curve approach, GCA) are applied to the formula to estimate total sediment transport rate. The graded sediment is sorted into specific fractions in the MFA, while divided into several equal fractions in the GCA. The formula is verified by instantaneous and net sediment transport rate data. The predictions of MFA and GCA are basically identical for instantaneous sediment transport rate and the overall accuracy is good. The gradation effect can increase or decrease the magnitude of instantaneous sediment transport rate, which depends on the behaviors and interactions of different fractions. Fractional net sediment transport rate is estimated by the formula with the MFA, which reasonably reproduces the onshore- or offshore-directed sediment transport for each fraction compared with existing formulae and numerical model. The performance of fraction number is discussed using the GCA. The proposed formula is capable of efficiently handling the graded sediment transport in wave-driven sheet flow.
Highlights Fractional formula is proposed for graded sediment transport in wave-driven sheet flow. Gradation effect is included through hiding-exposure factor of exposure height. Formula incorporates phase lag, acceleration effect and asymmetric boundary layer development. Two approaches (MFA and GCA) are employed to handle total sediment transport. Results reproduce promotion/inhibition and onshore/offshore sediment transport for each size fraction.
Fractional formula of sediment transport rate for graded sediment in wave-driven sheet flow
Coastal Engineering ; 180
2022-12-15
Article (Journal)
Electronic Resource
English
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