Campuses:

<span class=strong>Reception and Poster Session</span><br><br/><br/><b>Poster submissions welcome from all participants</b><br><br/><br/><a<br/><br/>href=/visitor-folder/contents/workshop.html#poster><b>Instructions</b></a>

Tuesday, April 12, 2011 - 3:30pm - 5:30pm
Lind 400
  • Coupling of Navier-Stokes/Darcy flow with transport
    Aycil Cesmelioglu (University of Minnesota, Twin Cities)
    We study a convection-diffusion type transport equation that is fully coupled to the Navier-Stokes/Darcy flow via velocity field and concentration. This problem is related to the groundwater contamination through rivers. On the interface, we accept balance of forces, continuity of the flux and the Beavers-Joseph-Saffman condition. Existence of a weak solution is shown by a method based on Galerkin approach in time. Furthermore, for the special case where the coupling is only one way via the velocity, we provide numerical analysis and simulations with methods based on continuous and discontinuous Galerkin methods.
  • A High-Order Finite-Volume Scheme for the Dynamical Core of Weather and Climate Models
    Christiane Jablonowski (University of Michigan)
    Joint work with Paul A. Ullrich (University of Michigan).

    The future generation of atmospheric models used for weather and climate predictions will likely rely on both high-order accuracy and Adaptive Mesh Refinement (AMR) techniques in order to properly capture the atmospheric features of interest. We present our ongoing research on developing a set of conservative and highly accurate numerical methods for simulating the atmospheric fluid flow (the so-called dynamical core). In particular, we have developed a fourth-order finite-volume scheme for a nonhydrostatic dynamical core on a cubed-sphere grid that makes use of an implicit-explicit Runge-Kutta-Rosenbrock time integrator and Riemann solvers. The poster surveys the algorithmic steps, presents results from idealized dynamical core test cases and outlines the inclusion of AMR into the model design.
  • An Investigation of the Forerunner Surge Produced by Hurricane Ike on the Texas and Louisiana Shelf
    Joannes Westerink (University of Notre Dame)
    A large, unpredicted, water level increase appeared along a
    substantial section of the western
    Louisiana and northern Texas (LATEX) coasts 12-24 hrs in
    advance of the landfall of Hurricane
    Ike (2008), with water levels in some areas reaching 3m above
    mean sea level. During this time
    the cyclonic wind field was largely shore parallel throughout
    the region. A similar early water
    level rise was reported for both the 1900 and the 1915
    Galveston Hurricanes. The Ike forerunner
    anomaly occurred over a much larger area and prior to the
    primary coastal surge which was
    driven by onshore directed winds to the right of the storm
    track. We diagnose the forerunner
    surge as being generated by Ekman setup on the wide and shallow
    LATEX shelf by simulating the hindcast with
    Coriolis turned on and off as well as with various frictional
    formulations. The longer
    forerunner time scale additionally served to increase water
    levels significantly in narrow entranced
    coastal bays.

    The forerunner surge generated a freely propagating continental
    shelf wave with greater than
    1.4m peak elevation that travelled coherently along the coast
    to Southern Texas, and was 300km
    in advance of the storm track at the time of landfall. This
    was, at some locations, the largest
    water level increase seen throughout the storm, and appears to
    be the largest freely-propagating
    shelf wave ever reported. Ekman setup-driven forerunners will
    be most significant on wide,
    forecasting in these cases.

    Reference:

    Kennedy, A.B., U. Gravois, B.C. Zachry, J.J. Westerink, M.E.
    Hope, J.C. Dietrich, M.D. Powell, A.T. Cox, R.A. Luettich, R.G.
    Dean, Origin of the Hurricane Ike Forerunner Surge,
    Geophysical Research Letters, In Press, 2011.
  • Meridional Asymmetries in Geophysical Flows
    Iordanka Panayotova (Old Dominion University)
    Geostrophic turbulence on a surface of a rotating sphere (so called beta-plane turbulence) has been simulated using the newly developed beta-sQG+1 numerical model. This model incorporates higher order terms beyond the standard quasi-geostrophy. The domain occupied by the fluid has a channel geometry with 512 by 256 grid points, periodic boundary conditions in x-direction and rigid boundaries in y-direction. To better understand wave-vortices dynamics both cases, with and without random forcing, are investigated. Both simulations start from identical random initial conditions and exhibit different dynamical properties.
    In the freely evolving case, adding a wave term that competes with inertia on larger scales produces high meridional asymmetry in eddies spatial and time scales. This novel asymmetry is added to the standard for the beta-plane turbulence zonal asymmetry. The model in the forced regime exhibits not only anisotropy in eddies deformation radius, but also in their orientation. The warm anomalies are elongated in the north-western direction, while the cold anomalies are elongated in the north-eastern direction. As a result there is a meridional meandering in the formed zonal jets.
  • Modeling of tsunami wave generation
    Dimitrios Mitsotakis (University of Minnesota, Twin Cities)
    We propose a simple and computationally inexpensive model for the
    description of the sea bed displacement during an underwater
    earthquake, based on the finite fault solution for the slip
    distribution under some assumptions on the dynamics of the rupturing
    process. Once the bottom motion is reconstructed, we study waves
    induced on the free surface of the ocean using three different models
    approximating the Euler equations of the water wave theory. The
    developments of the present study are illustrated on the July 17, 2006
    Java event.
  • Separation of Time Scales in fast rotation and weak stratification
    Beth Wingate (Los Alamos National Laboratory)
    In this work we discuss separation of time scales for rotating and stratified flow in the limit of fast rotation and weak stratification.