Friends and Community Business and Government Alumni Parents and Prospective Students Faculty and Staff Students
George Mason University
GMU Fairfax Campus
Today @ Mason

School of Computational Sciences

CAMP Home
   People
   Research
   Simulation gallery
     Hurricane predictions
     ├ Higher-order upwind schemes on unstructured meshes
     Urban scale simulation
     Advanced statistical methods (neural networks)
   Publications
   Resources for students
   Data archive
   Annual conference
  
Computing resources
   Related links
  
About our webpage
   Contact us

Higher-order upwind schemes on unstructured meshes

Higher-order finite volume solvers have been developed for the atmospheric transport equation as well as the Navier-Stokes equations. The solver is based on unstructured triangular grids in two dimensions. Different gradient reconstruction techniques have been tested to achieve higher-order accuracy in space and various slope limiters have been implemented to enforce monotonicity. Higher-order accuracy in time is maintained with the help of multi-stage Runge-Kutta explicit time-marching. Solution-adaptive techniques have also been used to demonstrate the computational efficiency associated with the use of unstructured grids.

a. Smolarkiewicz's Deformational Flow

Top left: Initial tracer field, top right: Initial flow field (streamfunction), bottom left: Tracer field at 1000 iterations, bottom right: Tracer field at 3000 iterations.


initial tracer field
streamfunction
tracer @ 1000 iter
tracer @ 3000 iter

For a description of this test case see: Smolarkiewicz, P. K., 1982: The multi-dimensional Crowley advection scheme. Mon. Wea. Rev., 113, 1050-1065.

b. Doswell's Frontogenesis

Top left: Initial tracer field, top right: Initial flow field (wind speed), bottom left: Numerical solution at time = 4 units, bottom right: Exact solution at time = 4 units.

initial tracer field
flow field
numerical solution exact solution

For a description of this test case see: Doswell, C., 1984: Kinematic Analysis of Frontogenesis Associated with a Nondivergent Vortex. J. Atmos. Sci., 41, 1242-1248.

c. LeVeque's Swirling Deformational Flow

Top left: Initial tracer field, top right: Initial flow field (wind speed), bottom left: Tracer field at 2300 iterations, bottom right: Tracer field at 4500 iterations.

initial tracer field wind speed
tracer at the 2300th iteration tracer at the 4500th iteration

For a description of this test case see: LeVeque, R. J., 1996: High-resolution conservative algorithms for advection in incompressible flow. SIAM J. Numer. Anal., 33, 627-665.

d. Convection in Neutral Atmosphere

Top left: Initial potential temp (K), top right: potential temp. (K) after 300s, middle left: u-velocity (m/s) after 300s and middle right: v-velocity (m/s) after 300s into the simulation, bottom left: density after 300s and bottom right: Mach number after 300s into the simulation.

initial potential temperature field potential temperature
u-velocity v-velocity
density Mach number

Atmospheric Flow Equation Set (Conservation of Energy in terms of rho-theta), Neutral Atmosphere in hydrostatic balance initially, Warm bubble added near the lower boundary - Velocities set to zero initially, Godunov Method with the HLLC Approximate Riemann Solver, 2D Unstructured Triangular Mesh, All boundaries treated as solid wall

See the contact page for detailed information on contacting us.

Validate this page with W3C