GfsAdvectionParams

From Gerris

GfsAdvectionParams is used to control the parameters of various advection schemes.

The syntax in parameter files is:

GfsAdvectionParams {
  cfl = 0.8
  gradient = gfs_center_van_leer_gradient
  scheme = godunov
  moving_order = 1
  vx = 0 vy = 0 vz = 0
}

where the parameters have been set to their default values and where

cfl

is the CFL number,

gradient

the function used to compute the gradient of advected variables. One of:

none

the gradient is set to zero (i.e. spatially first-order scheme),

gfs_center_gradient

second-order centered estimate (no limiter),

gfs_center_van_leer_gradient

van Leer generalised minmod limiter (θ = 2),

gfs_center_minmod_gradient

minmod limiter,

gfs_center_sweby_gradient

sweby limiter (β = 1.5),

gfs_center_superbee_gradient

superbee limiter.

scheme

either godunov for the default Godunov advection scheme, or none to switch advection off entirely,

moving_order

only relevant for GfsSimulationMoving, either 1 for the default first-order moving boundaries scheme, or 2 for the second-order scheme,

vx, vy, vz

the components of a "sinking velocity" to add when advecting a GfsVariableTracer. It can be functions. When present. it has to be specified ALL the components of the "sinking velocity" (vx and vy in 2D; vx, vy and vz in 3D). In addition, it is advisable that each component goes in separated lines.

Examples

• Dam break on complex topography

    AdvectionParams {
       # gradient = gfs_center_minmod_gradient
	gradient = none
    }

• Small amplitude solitary wave interacting with a parabolic hump

    AdvectionParams { cfl = 0.5 }

• Tsunami runup onto a complex three-dimensional beach

    AdvectionParams { gradient = gfs_center_sweby_gradient }

• The 2004 Indian Ocean tsunami

    AdvectionParams { gradient = gfs_center_sweby_gradient }

• Convergence for a simple periodic problem

  AdvectionParams { cfl = 0.75 }

• Convergence for the three-way vortex merging problem

  AdvectionParams { cfl = 0.9 }

• Potential flow around a sphere

    AdvectionParams { scheme = none }

• Bagnold flow of a granular material

    AdvectionParams {
	scheme = none
    }

• Creeping Couette flow of Generalised Newtonian fluids

  AdvectionParams { scheme = none }

• Convergence of a potential flow solution

    AdvectionParams { scheme = none }

• Flow through a divergent channel

    AdvectionParams { cfl = 0.9 }

• Potential flow around a thin plate

  AdvectionParams { scheme = none }

• Translation of an hexagon in a uniform flow

  AdvectionParams { 
      moving_order = ORDER 
      # uncommenting the following line leads to instabilities for the
      # first-order scheme 
      # cfl = 0.45
  }

• Circular droplet in equilibrium

  AdvectionParams { scheme = none }

• Axisymmetric spherical droplet in equilibrium

  AdvectionParams { scheme = none }

• Geostrophic adjustment

  AdvectionParams { scheme = none }

• Geostrophic adjustment with Saint-Venant

  AdvectionParams { gradient = gfs_center_gradient }

• Coastally-trapped waves

  AdvectionParams { scheme = none }

• Coastally-trapped waves with adaptive refinement

  AdvectionParams { scheme = none }

• Gravity waves in a realistic ocean basin

    AdvectionParams { scheme = none }

• Transcritical flow over a bump

    AdvectionParams { 
	# Sweby seems to work better than minmod for this test case
	gradient = gfs_center_sweby_gradient 
    }

• Transcritical flow with multiple layers

    AdvectionParams { 
	# Sweby seems to oscillate in this case
#	gradient = gfs_center_sweby_gradient 
    }

• Tsunami runup onto a plane beach

    AdvectionParams {
	gradient = gfs_center_sweby_gradient
    }

• Creeping Couette flow between cylinders

    AdvectionParams { scheme = none }

• Creeping Couette flow between eccentric cylinders

  AdvectionParams { scheme = none }

• Flow between eccentric cylinders using bipolar coordinates

  AdvectionParams { scheme = none }

• Flow between eccentric cylinders on a stretched grid

  AdvectionParams { scheme = none }

• Rossby--Haurwitz wave with Saint-Venant

    AdvectionParams { 
	gradient = gfs_center_gradient 
#	gradient = none
    }

• Simple example of groundwater flow following Darcy's law

    AdvectionParams { scheme = none }

• Groundwater flow with piecewise constant permeability

    AdvectionParams { scheme = none }