scholarly journals LITTORAL DRIFT AS FUNCTION OF WAVES AND CURRENT

1968 ◽  
Vol 1 (11) ◽  
pp. 26 ◽  
Author(s):  
E.W. Bijker
Keyword(s):  
Wave Motion ◽  
Sandy Beaches ◽  
Bed Load ◽  
Longshore Current ◽  
Littoral Drift ◽  
Engineering Research ◽  
Actual Computation ◽  
Load Transport ◽  
Bed Load Transport ◽  
The Waves

For the computation of littoral drift due to waves hitting a coast obliquely, most formulae are based upon the assumption that this longshore transport is some function of the energy flux of the waves towards the coast. For the actual computation the component of this flux parallel to the coast is introduced. Most of the available prototype data are incorporated m the formula of the U.S. Army Coastal Engineering Research Center (ref. 4 and 1). In this formula no reference is made to the gram size and the slopes of beach and foreshore. The explanation for the fact that nevertheless reasonable results are obtained is probably owing to the fact that variation of gram size and beach slope for sandy beaches is not so very great. A more serious disadvantage is, however, that it is not possible to take into account the influence of a possible longshore current which is not generated by the wave motion, such as for instance tidal currents. In this paper an attempt is made to compute the littoral drift, starting from the longshore current velocity as it is generated by the waves or as it may originate from other causes (ref. 4). For the actual computation of the bed load transport a normal bed load transport formula is used, in which, however, according to the method developed by the author in earlier studies, the bed shear is increased as a result of the wave motion (ref. 2). From the tests briefly described in the present paper it becomes clear that the transport may be treated indeed as a function of the longshore current, even when this current has a direction opposite to that of the component of the wave propagation parallel to the coast.

scholarly journals INFLUENCE OF GRAIN SIZE ON LITTORAL DRIFT

1970 ◽  
Vol 1 (12) ◽  
pp. 56 ◽  
Author(s):  
Jose Castanho
Keyword(s):  
Grain Size ◽  
Shear Stress ◽  
Bed Load ◽  
Flow Conditions ◽  
Littoral Drift ◽  
Flow Shear ◽  
Load Transport ◽  
Bed Load Transport ◽  
Flow Shear Stress ◽  
Load Discharge

Influence of grain size in sediment transport depends on flow conditions For bed load transport a maximum probably exists for load discharge as a function of gram size The important parameter seems to be the ratio To/T between the threshold shear stress and the flow shear stress.

scholarly journals BED LOAD TRANSPORT DUE TO NON-LINEAR WAVE MOTION

1988 ◽  
Vol 1 (21) ◽  
pp. 133 ◽  
Author(s):  
Hitoshi Tanaka
Keyword(s):  
Sediment Transport ◽  
Wave Motion ◽  
Surf Zone ◽  
Function Theory ◽  
Transport Rate ◽  
Bed Load ◽  
Linear Wave ◽  
Wave Flume ◽  
Load Transport ◽  
Bed Load Transport

The bed load transport rate due to wave motion is measured in a wave flume. The modified stream function theory of the author ( Tanaka (1988) ) is applied to the formulation of the sediment transport rate in order to include the non-linearity. The proposed formula predicts well except near the surf zone where the effect of the acceleration plays an important role.

scholarly journals QUANTITATIVE TRACING OF LITTORAL DRIFT

1968 ◽  
Vol 1 (11) ◽  
pp. 20
Author(s):  
Per Bruun
Keyword(s):  
Wave Action ◽  
Transport Layer ◽  
Hydraulic Lift ◽  
Bed Load ◽  
Wave Power ◽  
Fluorescent Tracers ◽  
Littoral Drift ◽  
Load Transport ◽  
Bed Load Transport ◽  
Horse Power

Tests were run at Fernandina Beach, Florida, using fluorescent tracers and bed load traps with automatic doors and hydraulic lift to determine the thickness of the bed load transport layer on the bottom ("bottom creep") (ref.l). Four special bed load traps with hydraulic remote controlled doors were installed on an ab. 800 ft. long pier. Fig. 1. Tracers of various colours were dumped at various distances from the pier. Two types of bottom profiles, Fig. 2, "berm profile" and Fig. 3, "bar-profile" were tested. As an example Fig. 4 shows test arrangement and wave action for test No. 17 (berm profile). Longshore wave power for this particular test was 1,5 Watts per ft of wave (one Watt is ab. 0,1 kg m/sec or ab. 0,0014- Horse Power), H, ,, was o,45 m, T, ,„ was 4-5 sec.

scholarly journals DISTRIBUTION OF SEDIMENT TRANSPORT ACROSS THE SURF ZONE

1972 ◽  
Vol 1 (13) ◽  
pp. 52 ◽  
Author(s):  
Edward B. Thornton
Keyword(s):  
Sediment Transport ◽  
Surf Zone ◽  
Sand Transport ◽  
Bed Load ◽  
Relative Distribution ◽  
Longshore Current ◽  
Energy Principle ◽  
Load Transport ◽  
Bed Load Transport ◽  
Wave Induced

The wave-induced sand transport alongshore is investigated by an energy principle approach. Although the energy approach has been used before, this is the first application to comparing theory and measurements of the distribution of littoral transport along a line perpendicular to the beach. Bed load transport equations are formulated for outside and inside the surf zone. Sand transport data were collected in the field using bed load traps. Wave, tide, wind, and current information was collected simultaneously in order to verify the derived predictive equations for longshore current and sediment transport. Quite reasonable predictions are obtained for the relative distribution of bed load transport, both inside and outside the surf zone.

NUMERICAL MODEL TO SIMULATE THE EROSION ON THE SLOPE DUE TO OVERTOPPING

2010 ◽  
Vol 13 (3) ◽  
pp. 78-87
Author(s):  
Hoai Cong Huynh
Keyword(s):  
Numerical Model ◽  
Flow Model ◽  
Bed Load ◽  
Experiment Data ◽  
Step Method ◽  
Morphological Model ◽  
Load Transport ◽  
Bed Load Transport ◽  
The Finite Difference Method ◽  
Good Agreement

The numerical model is developed consisting of a 1D flow model and the morphological model to simulate the erosion due to the water overtopping. The step method is applied to solve the water surface on the slope and the finite difference method of the modified Lax Scheme is applied for bed change equation. The Meyer-Peter and Muller formulae is used to determine the bed load transport rate. The model is calibrated and verified based on the data in experiment. It is found that the computed results and experiment data are good agreement.

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