Award Abstract # 0525729
Analytical and Numerical Studies of Deep Overflows and Related Circulations

NSF Org: OCE
Division Of Ocean Sciences
Recipient: WOODS HOLE OCEANOGRAPHIC INSTITUTION
Initial Amendment Date: August 26, 2005
Latest Amendment Date: August 26, 2005
Award Number: 0525729
Award Instrument: Standard Grant
Program Manager: Eric C. Itsweire
OCE
 Division Of Ocean Sciences
GEO
 Directorate for Geosciences
Start Date: September 1, 2005
End Date: August 31, 2010 (Estimated)
Total Intended Award Amount: $786,380.00
Total Awarded Amount to Date: $786,380.00
Funds Obligated to Date: FY 2005 = $786,380.00
History of Investigator:
  • Lawrence Pratt (Principal Investigator)
    lpratt@whoi.edu
  • Karl Helfrich (Co-Principal Investigator)
Recipient Sponsored Research Office: Woods Hole Oceanographic Institution
266 WOODS HOLE RD
WOODS HOLE
MA  US  02543-1535
(508)289-3542
Sponsor Congressional District: 09
Primary Place of Performance: Woods Hole Oceanographic Institution
266 WOODS HOLE RD
WOODS HOLE
MA  US  02543-1535
Primary Place of Performance
Congressional District:
09
Unique Entity Identifier (UEI): GFKFBWG2TV98
Parent UEI:
NSF Program(s): PHYSICAL OCEANOGRAPHY
Primary Program Source: app-0105 
Program Reference Code(s): 0000, OTHR
Program Element Code(s): 161000
Award Agency Code: 4900
Fund Agency Code: 4900
Assistance Listing Number(s): 47.050

ABSTRACT

Intellectual Merit:
This project seeks to extend our current understanding of deep overflows through a comprehensive study of rotating hydraulics of two-layer sill flows connected to broad basins. Two-layer dynamics are thought to be important in the overflows of a number of important passages, including the Denmark Strait, the Faroe-Bank Channel, and the Vema Channel, either in accounting for the influence of reverse flows at the surface or the evolution of distinct water masses feeding the channel and contained within the overflows. This study brings analytical and numerical techniques to bear on a number of fundamental issues including the dynamically consistent connection of two-layer hydraulic theory to the neighboring basin flows for both exchange and unidirectional flow cases, aspiration of deep layers, general methods for the identification of hydraulic control and the isolation of special features such as hydraulic jumps in channels with arbitrary cross section, and the role of time-dependence in straits and coupled basin-strait systems. The elucidation of these issues will aid in the interpretation of results from more complicated numerical models, observations, and in the planning of strategies for long-term monitoring of overflow transport from within upstream basins. Also, the investigators will continue to find ways of presenting the results so as to favor the intuition and to be accessible to the non-specialist.

Broader Impacts:
Deep passages offer ideal points to monitor the overturning circulation. However, this can only be done properly after development of hydraulic theories with improved realism and once the dynamical connections between strait and basin flows are understood. This work will begin to answer some of these questions and should be of wide interest beyond the specific dynamics explored here. The two investigators are both active in the MIT/WHOI Joint Program and the results of this research will quickly reach the classroom. A small percentage of the grant will support the completion of a graduate text on ocean strait and sill flow and other applications of hydraulics in geophysics. The grant will also provide continuing support for a graduate student to complete his thesis.

PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH

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(Showing: 1 - 10 of 15)
J. Girton, L. Pratt, D. Sutherland, J. Price "Hydraulic analysis of the Faroe-Bank Channel Overflow." Journal of Physical Oceanography , v.36 , 2006 , p.2340
K. Helfrich "Nonlinear adjustment of a localized layer of bouyant, nonuniform potential vorticity fluid against a vertical wall." Dynamics of Oceans and Atmospheres , v.41 , 2006 , p.149
Pickart, R. S., L. J. Pratt, D. J. Torres, T. E. Whitledge, A. Y. "Evolution and dynamics of the flow through Herald Canyon in the Western Canyon in the Western Chukchi Sea" Deep-Sea Research , 2009
Pickart, R. S., T. J. Weingartner, L. J. Pratt, S. Zimmermann, and D.Torres "Flow of winter-transformed Pacific water into the Western Arctic" Deep-Sea Research II , v.52(24-2 , 2005 , p.3175
Pratt, L.J. "Critical conditions and composite Froude numbers for layered flow with transverse variations in velocity" Journal of Fluid Mechanics , v.605 , 2008 , p.281
Pratt, L.J. "Critical conditions and composite Froude numbers for layered flow with transverse variations in velocity" Journal of Fluid Mechanics , v.605 , 2008 , p.281
Pratt, L. J. and K. R. Helfrich "Generalized Conditions for Hydraulic Criticality of Oceanic Overflows" Journal of Physical Oceanography , v.35(10) , 2005 , p.1782
Pratt, L. J. and K. R. Helfrich "Generalized Conditions for Hydraulic Criticality of Oceanic Overflows" Journal of Physical Oceanography , v.35(10) , 2005 , p.1782
Pratt, L. J. and K. R. Helfrich "On the stability of deep overflows" Journal of Fluid Mechanics , v.602 , 2008 , p.241
Pratt, L. J. and K. R. Helfrich "On the stability of deep overflows" Journal of Fluid Mechanics , v.602 , 2008 , p.241
Pratt, L. J. and K. R. Helfrich and D. Leen "On the stability of deep overflows" Journal of Fluid Mechanics , v.602 , 2008 , p.241
(Showing: 1 - 10 of 15)

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