Showing papers on "Wave flume published in 1989"
TL;DR: In this article, the dynamic pressure distribution around a large vertical cylinder resting on a flume bed and piercing the free surface subjected to regular waves have been carried out in a 4-m wide wave flume in a constant water depth of 2.5 m at Ocean Engineering Centre, Indian Institute of Technology, Madras, India.
24 citations
TL;DR: In this article, Bagnold's energetics approach is applied to cross-shore bed-load transport in a wave flume with movable bed and it is shown that the sediment transport is controlled primarily by asymmetric oscillatory motion of water superimposed on a steady return current, gravity, and the critical conditions of incipient sediment movement.
6 citations
TL;DR: In this paper, the theoretical expressions for near-bed, shorenormal flows are re-examined and the predictions are tested with morphodynamic and laboratory data, and the results suggest that Stokes wave theory over-predicts the observed peak flows.
Abstract: Although the near-bed, wave induced currents predicted by the various wave theories are responsible for seabed sediment transport, it is presently unclear which theory should be included in coastal geomorphic models. The theoretical expressions for near-bed, shorenormal flows are re-examined and the predictions are tested with morphodynamic and laboratory data. Five wave theories (Airy, Stokes, Cnoidal, Solitary, and Gerstner) are summarized here and arranged to predict the maximum onshore and offshore near-bed flows and the flow asymmetry as functions of the wave period, the wave height, and the water depth. Morphodynamic argument suggests that only Stokes and Cnoidal wave theories predict the asymmetry required to generate prototype seabed profiles in intermediate water depths. Laboratory measurements of wave induced near-bed flows are then reported and analysed. The results suggest that Stokes wave theory over-predicts the observed peak flows. A correction is derived which is shown to be analogous to the pressure attenuation corrections which are routinely applied to wave recording, seabed mounted transducer measurements.
5 citations
01 Jan 1989
TL;DR: In this paper, the results of experiments on heavily roughened cylinders in regular waves and linear oscillatory flow at Reynolds numbers in the range from 6x10E4 to 7.7x10 E5 and Keulegan Carpenter numbers from 1 to 29 were described.
Abstract: This paper describes the results of experiments on heavily roughened cylinders in regular waves and linear oscillatory flow at Reynolds numbers in the range from 6x10E4 to 7.7x10E5 and Keulegan Carpenter numbers from 1 to 29. The first set of experiments used a 521mm diameter vertical cylinder in the Delta wave flume of the Delft Hydraulics Laboratory. The second set of experiments used a 420mm diameter vertical cylinder mounted on a new underwater linear oscillatory carriage facility at the Marine Technology Centre of the University of Strathclyde. The experimental arrangements are described in both cases.
3 citations
TL;DR: In this article, the circulation of the vortices is estimated with potential flow theory, applying Kutta's condition at the crest of ripples, which indicates that the circulation has a functional relationship with period of fluid oscillation, boundary layer thickness and fluid velocity at the edge of the boundary layer.
Abstract: The present paper deals with vortex shedding from ripples and the associated wave energy dissipation. The circulation of the vortices is estimated with potential flow theory, applying Kutta's condition at the crest of ripples, which indicates that the circulation has a functional relationship with period of fluid oscillation, boundary layer thickness and fluid velocity at the edge of the boundary layer. The kinetic energy of the vortices is assumed to be dissipated to reduce the wave energy. A formula is derived under the assumption, and it is tested with wave flume experiment for which self-formed ripples are generated. A good correlation is found between the theory and the experimental result.
3 citations
01 Jan 1989
1 citations
Journal Article•
TL;DR: In this article, a 2D physical model was used to simulate wave-induced scour in front of a concrete dike sloped at 1:4.5 geometric scale as determined by the fall velocity parameter H/WT.
Abstract: A two-dimensional physical model was used to simulate wave-induced scour in front of a concrete dike sloped at 1:4. The tests were conducted at the U.S. Army Engineers Waterways Experiment Station during October - December, 1988. The primary purpose of the tests was to validate a proposed scaling relationship for movable-bed models by reproducing profile evolution observed in a large wave flume at the University of Hannover in the Federal Republic of Germany in 1985. The model was undistorted and was constructed at a 1:7.5 geometric scale as determined by the fall velocity parameter H/WT. Quartz sand with mean diameter 0.13 mm was used in the model to simulate prototype sand which had 0.33 mm mean diameter. Results indicated that scaling with the fall velocity parameter generates favorable profile replication for energetic processes such as scour or beach erosion.
1 citations
01 Jul 1989
TL;DR: In this paper, the results from mathematical models which have been used to calculate wave conditions in the vicinity of and island breakwater are presented for both monochromatic and random incident waves for normal and obliquely incident waves.
Abstract: This report presents the results from mathematical models which have been used to calculate wave conditions in the vicinity of and island breakwater. The main purpose of the research described here was to provide engineers with guidance on the performance of offshore breakwater in coast protection schemes. The report contains diffraction diagrams for both monochromatic and random incident waves for normal and obliquely incident waves. It also provide illustration of the use of these diagrams in selecting breakwater layout, and in calculating other important parameters such as wave run-up overtopping.
TL;DR: In this article, the circulation of the vortices is estimated with potential flow theory, applying Kutta's condition at the crest of ripples, which indicates that the circulation has a functional relationship with period of fluid oscillation, boundary layer thickness and fluid velocity at the edge of the boundary layer.
Abstract: The present paper deals with vortex shedding from ripples and the associated wave energy dissipation. The circulation of the vortices is estimated with potential flow theory, applying Kutta's condition at the crest of ripples, which indicates that the circulation has a functional relationship with period of fluid oscillation, boundary layer thickness and fluid velocity at the edge of the boundary layer. The kinetic energy of the vortices is assumed to be dissipated to reduce the wave energy. A formula is derived under the assumption, and it is tested with wave flume experiment for which self-formed ripples are generated. A good correlation is found between the theory and the experimental result.