New experiments were carried out in the Large Oscillating Water Tunnel of WL|Delft Hydraulics (scale 1:1) using asymmetric 2nd-order Stokes waves. The main aim was to gain a better understanding of size-selective sediment transport processes under oscillatory plane-bed/sheet-flow conditions. The new
The inception of sheet flow in oscillatory flow
โ Scribed by Zai-Jin You
- Book ID
- 104159313
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 229 KB
- Volume
- 26
- Category
- Article
- ISSN
- 0029-8018
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โฆ Synopsis
A simple model is developed to study the inception of sheet flow in oscillatory flow based on the available experimental data. The inception of sheet flow in oscillatory flow is well defined by the simple model: A/d = KA 2 / + B, where A is the semi-excursion of wave orbital motion near the bed, d is the grain size, is the angular frequency, is the kinematic viscosity of water, and K and B are the coefficients and dependent on sediment properties only. The inception velocity of sheet flow derived from the model is shown to be the function of grain size d, oscillatory period T and specific sediment density s. For a given sediment, the inception velocity is found to increase sharply initially with T and then approach a constant at T > 6.0 s. The present model is quite simple and gives good agreement with the available experimental data.
๐ SIMILAR VOLUMES
The method of Wang [Wang, Y.-H., 2007. Formula for predicting bedload transport rate in oscillatory sheet flow. Coastal Engineering 54, 594-601] to predict the wave friction factor is discussed. At the threshold of sediment entrainment the proposed equation produces a wide scatter of data points whe