Karl R. Helfrich

Senior Scientist

J. S. Johnson Chair and Education Coordinator

Department of Physical Oceanography, MS-21

Woods Hole Oceanographic Institution

Woods Hole, MA 02543

Tel: 508-289-2870

Fax: 508-457-2181

khelfrich@whoi.edu

Research Interests

Theoretical and laboratory studies in geophysical fluid dynamics: stratified flows and internal waves, hydraulic phenomena, abyssal circulation in the presence of topography, and geological fluid dynamics.

Current Research Projects

Rotating hydraulics: the establishment of steady solutions due to Gill (1977), the structure and dynamics of hydraulic jumps and shocks, and the connection between the upstream basin circulation and the hydraulically controlled strait flow.  

Coastal buoyancy currents: the development and testing of a scaling theory for intrusion speed and structure of the stratification and flow field of buoyant intrusions over a slope (e.g., estuary outflow). 

Potential vorticity fronts: theoretical, numerical and experimental study of the intrusion of a potential vorticity front along a boundary in a rotating system.

Island circulations: the dynamics of abyssal and upper wind driven oceanic flow around planetary scale ridges and islands.

Recent publications

Helfrich, K. R. and L. J. Pratt, Rotating hydraulics and upstream basin circulation. J. Physical Oceano., submitted. HP-JPO.pdf

Helfrich, K. R. and J. Pineda, Accumulation of particles in propagating fronts. Limnology and Oceanography, submitted. HP-LO.pdf

Stern, M. E. and K. R. Helfrich, 2002. Propagation of a finite amplitude potential vorticity front along the wall of a stratified fluid. J. Fluid Mech., 468, 179-204. SH-JFM.pdf

Lentz, S. J. and K. R. Helfrich, 2002. Buoyant gravity currents along a sloping bottom in a rotating fluid. J. Fluid Mech., 464, 251-278.  LH-JFM.pdf

Wells, J. R. and K. R. Helfrich, 2001. Circulation around a thin zonal island. J. Fluid Mech. 437, 301-323.

Pratt, L. J., K. R. Helfrich and E. P. Chassignet, 2000. Hydraulic adjustment to an obstacle in a rotating fluid. J. Fluid Mech. 404, 117-149.

Helfrich, K. R., A. C. Kuo and L. J. Pratt, 1999. Nonlinear Rossby adjustment in a channel. J. Fluid Mech. 390, 187-222.

Useful links

Education: WHOI Education Program

Professional Societies: American Geophysical Union , European Geophysical Society , American Meteorological Society , American Physical Society , Institute of Physics

Journals: (mostly tables of contents) Nature , Science , Journal of Fluid Mechanics , Physical Review , Journal of Geophysical Research , AMS Journals , Dynamics of Atmospheres and Oceans , Deep Sea Research , Progress in Oceanography , Physics of Fluids , Journal of Computational Physics .