APL Colloquium

April 25, 2008

Colloquium Topic: Waves, Fish, and Submarines: Thirty Years of Hydrodynamics Research at APL

In the early 1970's, at the outset of a national program to ensure survivability of the US submarine fleet, relatively little was known about the wake signatures generated by submarine motions in the ocean or about the nature of the small-scale ocean processes that influence those signatures. At that time research studies (laboratory and analytic) were initiated to provide a basic understanding of the relevant physical processes. These research studies led to a major ocean field program that continues at the Laboratory to this day. Also ongoing is the basic research effort into wake physics and oceanic processes that have been carried out in the flow channel and tow tank situated in the APL Hydrodynamics Research Laboratory. This facility is a unique national resource focused on emulating the stratified flows that exist in the ocean and atmosphere. The scope of our research effort has grown beyond issues related to submarine security to include a broad range of fundamental studies in the environmental sciences, including efforts ranging from ocean internal waves to mixing in the Chesapeake Bay to underwater propulsion by biomimetic ribbon fins as found on certain fish and eels. The history, motivation, and underlying scientific challenges of our efforts in ocean hydrodynamics will be revealed.

Colloquium Speaker: Alan Brandt

Alan Brandt received a Bachelor of Civil Engineering from The Cooper Union and M.S. and Ph.D. degrees in Civil Engineering from Carnegie Mellon University. Upon graduation he joined the Johns Hopkins University Applied Physics Laboratory. In 1971 he was on sabbatical at the Imperial College in London, working on intermittent turbulent flows, and from 1987 to 1993 he was Program Manager for the Physical Oceanography and Coastal Sciences Programs at the Office of Naval Research. Upon returning to APL he was re-appointed to the Principal Professional Staff, and currently he also has a joint appointment in the JHU Dept. of Mechanical Engineering. His research includes studies in fluid dynamics, physical oceanography, and environmental sciences, specifically surface and subsurface hydrodynamics, internal waves, turbulence, and issues related to submarine security. Recently he has been working on stratified wakes and the associated low Froude number internal waves, development of an expert system model for sea mine burial, characterization of the effects of episodic events (e.g. storms) on the near surface ocean, and biomimetic propulsion for application to underwater vehicles.