Delft-AUKE
high-quality wave generation for experimental research
| Experimental facilities are often used when the physics involved are (still) too complex to use computer methods. Typical examples of these investigations are coastal infrastructural design (such as breakwaters, sea dykes), offshore structures (e.g. oil rigs) and naval architecture (ship design). In many cases, the objective of experiments is to determine the structure's response to wave forces and other wave-induced processes (such as run-up, overtopping, etc.). Therefore, it is essential to be able to generate highly accurate waves in order to obtain high-quality research experiments.
Deltares has developed a second-order wave generation algorithm named Delft-AUKE/generate, which is designed to produce accurate waves by suppressing of spurious components while simultaneously absorbing reflected waves at the wave maker.
The algorithm can be used in both wave flumes and wave basins, and for both 'piston' and 'flap'-type wave generators with a hinge positioned at arbitrary depth above or below the bottom. Using this software constant, bichromatic and irregular (short- and longcrested) waves can be generated according to a prescribed energy density function.
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Figure a) shows an example of a short-crested wave field. The top panel is the measured wave field in the directional wave bassin, while the bottom panel is the target directional spreading. Also, almost any desired wave field can be reproduced at a prescribed location. An Active Reflection Compensation (ARC) algorithm has been developed which compensates the wave board motion for reflected short waves from an arbitrary angle by using a wave height meter which is flush-mounted on the wave boards. In effect, the wave board generates 'anti' waves which counterbalance the reflected wave at the wave board.
Figure b) shows an incident wave train towards the wave board equipped with ARC and its reflection from the wave board later in time, which is attenuated significantly by the ARC.
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Figure a
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Measured (top) vs. target (bottom) directional spreading.
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Figure b
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Incident and reflected waves on the wave board equipped with ARC.
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Delft-AUKE/generate has been thoroughly tested and installed at Deltares' own flumes and basins. In cooperation with Rexroth/Hydraudyne who constructed the generator equipment, this wave generation and absorption software has been implemented at the Marin Laboratory Facilities in Wageningen,
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more information
For more information please contact Ivo Wenneker.
Copyright © 2010, Deltares.
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