BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:The Interaction between Gravity Currents and Breaking Internal Wav
 es - Professor Jeffrey Koseff\, Stanford
DTSTART:20231012T103000Z
DTEND:20231012T113000Z
UID:TALK206704@talks.cam.ac.uk
CONTACT:Catherine Pearson
DESCRIPTION:Gravity currents moving along the continental slope\, such as 
 cold river inflows into lakes or brine effluent from desalination plants\,
  can be influenced by internal waves shoaling on the slope resulting in mi
 xing between the gravity current and the ambient fluid. Whilst some observ
 ations of the potential influence of internal waves on gravity currents ha
 ve been made\, the process has not been studied systematically. I will pre
 sent the results of laboratory experiments in which a gravity current desc
 ends down a sloped boundary through a pycnocline at the same time as an in
 ternal wave at the pycnocline shoals on the slope. The waves are generated
  in a two-layer thin-interface ambient water column under a variety of con
 ditions characterizing both the waves and the gravity currents.\n\nFrom th
 e experiments we have learned that the presence of a pycnocline causes a g
 ravity current to split and intrude into the ambient at two distinct level
 s of neutral buoyancy\, as opposed to the classical description of gravity
  currents in stratified media as being either a pure under or interflow. A
 dditionally\, we have also identified two different types of waves that fo
 rm on the pycnocline in response to the intrusion of the gravity current. 
 An underflow-dominated regime causes a pycnocline displacement where the s
 peed of the wave crest is locked to the gravity current\, whereas an inter
 flow-dominated regime launches an internal wave that moves much faster tha
 n the gravity current head or interfacial intrusion.\n\nWe also completed 
 a full set of experiments investigating the effects of the basin walls int
 eracting with the initiated waves and characterized the reflected waves an
 d subsequent mixing efficiencies. From these longer time scale experiments
  we have identified two modes of motion initiated by the interaction. Firs
 t\, there is a low frequency surge of the lower layer caused by the gravit
 y current\, and also higher frequency internal waves that break when they 
 encounter the topographic slope and quickly dissipate. The mixing efficien
 cy of the reflected internal waves breaking on the topographic slope was q
 uantified as an overall mixing efficiency (across all wave breaking events
 ) and was found to be low compared to previous similar studies. \n
LOCATION:Open Plan Area\, Institute for Energy and Environmental Flows\, M
 adingley Rise CB3 0EZ
END:VEVENT
END:VCALENDAR