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SUMMARY:Discrete-element models of sea ice dynamics and fracture - Agniesz
 ka Herman (University of Gdansk)
DTSTART:20170911T104500Z
DTEND:20170911T113000Z
UID:TALK78672@talks.cam.ac.uk
CONTACT:INI IT
DESCRIPTION:At geophysical scales\, continuum models provide established a
 nd computationally efficient tools for simulating sea ice dynamics and the
 rmodynamics. In recent years\, rapidly increasing computational power and 
 availability of high-resolution (esp. remote-sensing) data have contribute
 d to a revival of discrete-element methods (DEM)\, enabling the analysis o
 f sea ice at smaller spatial and temporal scales. Treating sea ice as a co
 llection of individual\, interacting floes\, and thus recognizing it as an
  example of a granular material\, opens a wide range of new tools and anal
 ysis possibilities for sea ice research. Bonded-particle DEM models enable
  to simulate brittle fragmentation of sea ice &ndash\; a process that\, in
  spite of substantial progress in recent years\, still poses problems for 
 continuum models. Moreover\, there is growing evidence that the size distr
 ibution of sea ice floes has a substantial influence on a wide range of pr
 ocesses in the upper ocean\, lower atmosphere and within sea ice itself\, 
 and it is in turn shaped by those processes. By directly taking into accou
 nt fragmentation (i.e.\, floe formation) and dynamics of individual floes\
 , DEMs provide tools to better understand complex interactions between sea
  ice\, ocean and atmosphere acting at the floe-level.<br><br><span>In this
  talk\, I will present and discuss selected examples of the application of
  DEM models to sea ice dynamics and fragmentation problems. The examples w
 ill include: wind- and current-induced drift of fragmented (``granular&rsq
 uo\;&rsquo\;) sea ice\, and the influence of ice concentration and floe-si
 ze distribution on the sea ice response to forcing\; jamming phase transit
 ion under compressive and shear strain\, and force transmission in ice sub
 ject to different strain fields\; sea ice breaking by waves analyzed with 
 a coupled DEM&ndash\;hydrodynamic model. Unsolved problems and challenges 
 (both computational and theoretical) related to the application of DEMs to
  sea ice will be presented as well.<br><br></span><span>Most results prese
 nted in this talk were obtained with a Discrete-Element bonded-particle Se
 a Ice model DESIgn\, implemented as a toolbox for the open-source numerica
 l library LIGGGHTS (<a target="_blank" rel="nofollow" href="http://www.cfd
 em.com/">http://www.cfdem.com/</a>). The code and documentation of DESIgn 
 are freely available at <a target="_blank" rel="nofollow" href="http://her
 man.ocean.ug.edu.pl/LIGGGHTSseaice.html">http://herman.ocean.ug.edu.pl/LIG
 GGHTSseaice.html</a>.</span>  <br><br><br><br>
LOCATION:Seminar Room 1\, Newton Institute
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