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Docking Structures & Wave Energy. Nick Ripp William Marcouiller. Introduction. Flow past obstacles Relate to dock and bridge piers High and low energy waves Sediment disruptions Design strength for piers and dock legs. www2.icfd.co.jp. Motivation. Experiment. Simulate incident waves - PowerPoint PPT Presentation
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Docking Structures & Wave Energy
Nick RippWilliam Marcouiller
Introduction
• Flow past obstacles
• Relate to dock and bridge piers
• High and low energy waves
• Sediment disruptions
• Design strength for piers anddock legs
www2.icfd.co.jp
Motivation
Experiment
• Simulate incident waves• Estimate wave energy before and after structural
contact by measuring wave height• Determine if major differences occur• Why or why not?
– Geometric violations– Reflections and diffractions– Intensity of wave energy
• Apply to real settings
Experiment
• Physical modeling: similitude requirements– Geometric similarity (linear dimensions)– Kinematic similarity (motion between particles)– Dynamic similarity (vectorial forces)
• Perfect similitude requires that the prototype-to-model ratios of the inertial, gravitational, viscous, surface tension, elastic, and pressure forces be identical.
Setup
2 feet
11 feet
‘Coastal Structures’
Objects used:
4x4 inch rectangular wooden support orthogonal to flow
4x4 inch rectangular wooden support oblique to flow (≈45⁰)
4 inch diameter cylindrical aluminum support
4x4 Orthogonal Square
4x4 Oblique Square
4 inch Diameter Cylinder
No Obstacles
4x4 Orthogonal Square Analysis
4x4 Oblique Square Analysis
4 inch Diameter Cylinder
2 Obstacles
Orthogonal Block Oblique Block
vs
2 Obstacles
Cylinder
Analysis
Controlled period
Measured depth
Observed wave height
Approximate energydensity after collision with obstacle
2 seconds
6 inches (.1524 meter)
6 inches (.1524 meter)
28.5 N-m/m2
Analysis
Since the waves were partially spilling over, a more accurate calculation of energy density is given by the University of Delaware Wave Calculator. It found the energy density to be approximately 18.2 Nm/m2.
Analysis
Calculated wave length
Calculated wave height
Wave steepness
2.4 meter
.1219 meter (breaking)
.05079
Conclusion
• If wave energy varies significantly in the direction normal to wave propagation, wave energy can be transmitted laterally due to wave diffraction in addition to the direction of wave propagation
• Wave diffraction also occurs in the sheltered region behind barriers and obstacles
• Wave reflection occurs when waves come into contact with obstacles
Conclusion
• Encourage dock industry to produce innovative designs that have less of an impact on the coastal environment
• Educate coastal landowners• Restricting the amount of
coastal area disturbed minimizes impacts
Bibliography
Acknowledgments
Professor Chin Wu
Minnesota DNRhttp://www.dnr.state.mn.us/waters/watermgmt_section/pwpermits/docks.html
http://files.dnr.state.mn.us/waters/watermgmt_section/pwpermits/dock_platform_general_permit_q_and_a.pdf
Mohn, Magoon, Pirrell. (2003). Advances in coastal structure design. ASCE
Wisconsin DNRdnr.wi.gov/
University of Delaware: Wave Calculator