LABORATORY STUDY ON SAND TRANSPORT OVER RIPPLES DUE TO ASYMMETRIC OSCILLATORY FLOWS

Mechanism of sand movement due to asymmetric oscillatory flows was investigated through experiments. Measurements of bed forms, suspended sand concentration and net sand transport rate were carried out by using an oscillatory flow tunnel. The process of entrainment and suspension of sand above asymmetric ripples was quantitatively described. The geometry of ripples and the net sand transport rate in regular and irregular flows were expressed in terms of hydraulic parameters characterizing the oscillatory flow. Two-dimensionality of ripples was found to be an important factor in the estimation of the net sand transport rate.

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CALCULATION OF ON-OFFSHORE SAND MOVEMENT AND WAVE DEFORMATION ON TWO-DIMENSIONAL WAVE-CURRENT COEXISTENT SYSTEM

Coastal Engineering Proceedings ◽

10.9753/icce.v21.90 ◽

1988 ◽

Vol 1 (21) ◽

pp. 90

Author(s):

Koichi Kinose ◽

Shuji Okushima ◽

Masahito Tsuru

Keyword(s):

Wave Height ◽

Experimental Results ◽

Breaking Point ◽

Transport Rate ◽

Sand Transport ◽

Height Distribution ◽

Wave Deformation ◽

Sand Transport Rate ◽

Sand Drift ◽

Sand Movement

In this paper, we proposed a method of calculation to predict quantitatively the on-offshore sand movement and the wave deformation on a wave-current coexistent system by assuming a river mouth. And the calculated results were compared with the experimental data obtained for the coexistent system in a twodimensional wave tank. The distribution of wave height on the breaker zone was analyzed by use of BORE MODEL. It was required for the calculation of the sand transport rate. The model was established on the assumption that the value of energy loss in a breaking wave was equivalent to that of bore. The wave height distribution on the offshore side of breaking point was presumed employing the third order approximate solution of Stokian wave on the coexistent system. The breaking point was obtained by use of Miche's criteria equation. The local sand transport rate could be calculated by use of POWER MODEL. The predominant direction of sand drift was recognized using relations for judgement which were derived from the experimental results. The transformation of sea bottom and river one was estimated on the basis of the calculated distributions of the wave height and the sand transport rate. The results obtained by this analytical method agreed well with the experimental results.

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Geometry of Sand Ripples and Net Sand Transport Rate Due to Regular and Irregular Oscillatory Flows

Coastal Engineering in Japan ◽

10.1080/05785634.1988.11924477 ◽

1988 ◽

Vol 30 (2) ◽

pp. 89-98 ◽

Cited By ~ 4

Author(s):

Shinji Sato ◽

Kuniaki Mitani ◽

Akira Watanabe

Keyword(s):

Transport Rate ◽

Sand Transport ◽

Oscillatory Flows ◽

Sand Ripples ◽

Sand Transport Rate

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TOWARD AN IMPROVED EMPIRICAL FORMULA FOR LONGSHORE SAND TRANSPORT

Coastal Engineering Proceedings ◽

10.9753/icce.v21.88 ◽

1988 ◽

Vol 1 (21) ◽

pp. 88 ◽

Cited By ~ 3

Author(s):

Nicholas C. Kraus ◽

Kathryn J. Gingerich ◽

Julie Dean Rosati

Keyword(s):

Oscillatory Flow ◽

Field Experiments ◽

Surf Zone ◽

Transport Rate ◽

Sand Transport ◽

Longshore Current ◽

Wave Energy Dissipation ◽

Total Transport ◽

Local Wave ◽

Correction Terms

This paper presents results of two field experiments performed using portable traps to obtain point measurements of the longshore sand transport rate in the surf zone. The magnitude of the transport rate per unit width of surf zone is found to depend on the product of the local wave height and mean longshore current speed, but correlation is much improved by including two correction terms, one accounting for local wave energy dissipation and the other for the fluctuation in the longshore current. The field transport rates are also found to be compatible with laboratory rates obtained under combined unidirectional and oscillatory flow. Total transport rates previously reported for this experiment program are revised with recently determined sand trapping efficiencies.

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