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Goddard Space Flight Center, Greenbelt, Maryland 20771

ENGINEERING COLLOQUIUM

Monday, May 9, 2011 / 3:30 PM, Building 3 Auditorium

Tony Dalrymple

"Hurricanes, Tsunamis, and Coastal Engineering"

ABSTRACT -- Coastal engineering usually only makes headlines during disasters, like the Indian Ocean tsunami or Hurricane Katrina. This talk will discuss those events, based on the speaker's first-hand inspections of the aftermath. Along the way, the talk will introduce various aspects of coastal engineering, which is the study of the natural environment of the coastline and its interaction with engineered structures.

In New Orleans, much of the damage was caused not when water overflowed the levees, but when water undermined the levees, allowing them to collapse. The fix for that problem is a matter of engineering, specifically of building proper foundations. Planning the future of New Orleans will depend on more than just engineering, however. It will also depend on the condition of the land between the city and the coast. The presence of wetlands on the shore can help reduce the storm surge, for instance. The wetlands, in turn, depend on the Mississippi River delta, which has been eroding at 75 square kilometers per year for decades.

Damage from the Indian Ocean tsunami provides some lessons learned for future coastal protection. For example, a seawall built with openings to allow pedestrian access to the beach also allowed wave access to the buildings behind the wall. Another wall with a top that sloped away from the water served as a launching ramp that guided the wave into the second floor of nearby buildings. On the other hand, vertical barriers helped deflect wave energy.

One of the important tools for coastal engineers is the modeling of hurricane storm surge and tsunami propagation and inundation. One such tool under development is GPUSPH--a Smoothed Particle Hydrodynamics Graphics Card accelerated model for free surface flows. Some examples will be shown.

SPEAKER -- Dr. Robert Anthony Dalrymple has been the Willard & Lillian Hackerman Professor of Civil Engineering at Johns Hopkins University since 2002. Prior to that time he was the E.C. Davis Professor of Civil Engineering and founder of the Center for Applied Coastal Research at the University of Delaware, where he taught for 29 years.

His research is in the field of coastal engineering, including water waves and their impact on shorelines, structures, and the ocean bottom and natural hazards, such as rip currents and tsunamis.

He began studying coastal processes early in life, learning to wind surf and scuba dive. At Dartmouth, he majored in engineering. He originally intended to work on designing underwater habitats, but moved his focus to shallower water when he discovered coastal engineering. After getting his master's degree at the University of Hawaii, he moved on to the University of Florida. He obtained his Ph. D. there, studying the interaction of waves on offshore oil rigs.

He is a member of the disaster response team of the American Society of Civil Engineers. As part of the team, he visited Thailand after the tsunami and New Orleans after Katrina. He chaired the National Research Council's committee on protecting and restoring the Louisiana coast. He is a member of the National Academy of Engineering.

His publications include two textbooks, Water Wave Mechanics for Engineers and Scientists and Coastal Processes with Engineering Applications. Both were co-authored with R. G. Dean, who was his Ph. D. advisor.

He helped develop the open source Graphical Processing Unit Smooth Particle Hydrodynamics (GPUSPH) program, which runs on an Nvidia graphics card.

He plays guitar (both flamenco and classical) and has consulted for art projects, including the wave pool in front of the NOAA office buildings on East West Highway in Silver Spring, Maryland.

He still enjoys visiting the beach and analyzing the incoming waves. But since not everyone in his family enjoys the analysis as much as he does, most of his recent vacation trips have been to the mountains.




Engineering Colloquium home page: https://ecolloq.gsfc.nasa.gov