GfsSolid

From Gerris

GfsSolid is used to define solid boundaries. By default the boundary conditions are no-slip for velocity and zero normal gradient for tracers (use GfsSurfaceBc to change this).

The syntax in parameter files is:

[ GfsEvent ] [ GfsSurface ]

If GfsSurface is defined implicitly, by convention the fluid domain is the locus of points for which the implicit function takes positive values.

Note that in order to use a full C function (in contrast to a C expression) as surface definition, the function definition must be "protected" with straight brackets for example this:

Solid {
  double r = 0.0625;
  return x*x + y*y - r*r; 
}

will not work but this will:

Solid ({
  double r = 0.0625;
  return x*x + y*y - r*r; 
})

Examples

• B\'enard--von K\'arm\'an Vortex Street for flow around a cylinder at Re=160

  Solid (x*x + y*y - 0.0625*0.0625)

• Vortex street around a "heated" cylinder

  Solid (x*x + y*y - 0.0625*0.0625)

• Parallel simulation on four processors

  Solid (x*x + y*y - 0.0625*0.0625)

• Boussinesq flow generated by a heated cylinder

  Solid (ellipse(0.,-0.15,1./16.,1./16.))

• Starting vortex of a NACA 2414 aerofoil

  Solid AEROFOIL.gts { rz = -INCIDENCE }

• Viscous folding of a fluid interface

    Solid ({
        return y - (floor_depth - cavity_depth);
    })

• Turbulent air flow around RV Tangaroa

  Solid tangaroa.gts

• Air-water flow around a Series 60 cargo ship

    Solid S60-scaled.gts { ty = 0.5 }

• Wingtip vortices behind a rectangular NACA 2414 wing

  Solid AEROFOIL.gts { rz = -INCIDENCE }

• Lunar tides in Cook Strait, New Zealand

    Solid bath.gts

• Shock reflection by a circular cylinder

    Solid (sphere(-0.5,0.,0.,0.5))

• Dirichlet boundary condition

    Solid ({
            double theta = atan2 (y, x);
            double radius = 0.30 + 0.15*cos (6.*theta);
            return radius*radius - x*x - y*y;
    })

• Convergence of the Poisson solver with solid boundaries

  Solid (ellipse (0, 0, 0.25, 0.25))

• Star-shaped solid boundary with refinement

    Solid ({
            double dr = 0.1;
            double theta = atan2 (y, x);
            double radius = 0.79*(0.45 - dr + dr*cos (6.*theta));
            return x*x + y*y - radius*radius;
          })

• Star-shaped solid boundary

    Solid ({
            double dr = 0.1;
            double theta = atan2 (y, x);
            double radius = 0.79*(0.45 - dr + dr*cos (6.*theta));
            return x*x + y*y - radius*radius;
          })

• Poisson solution in a dumbbell-shaped domain

  Solid dumbell.gts

• Comparison between the explicit and implicit diffusion schemes

    Solid (-sphere(0,0,0,0.4))

• Potential flow around a sphere

    Solid (ellipse (0., 0., A0, A0))

• Viscous flow past a sphere

    Solid (ellipse (0., 0., A0, A0))

• Mass conservation with solid boundary

    Solid (ellipse (0., 0., 0.05, 0.05))

• Creeping Couette flow of Generalised Newtonian fluids

  Solid (ellipse (0,0,0.25,0.25)) { flip = 1 scale = 1.9999 }

  Solid (ellipse (0,0,0.25,0.25))

• Hydrostatic balance with solid boundaries and viscosity

    Solid (ellipse(0.,0.,0.24,0.24))

• Hydrostatic balance with quadratic pressure profile

    Solid (ellipse(0.,0.,0.24,0.24))

• Convergence of a potential flow solution

    Solid (ellipse (0.25, 0.25, 0.1, 0.1))

    Solid (ellipse (-0.25, 0.125, 0.15, 0.1))

    Solid (ellipse (0., -0.25, 0.2, 0.1))

• Flow through a divergent channel

    Solid (0.125 - channel (x) - y) { scale = 4 tx = 1.5 }

    Solid (y + 0.125 - channel (x)) { scale = 4 tx = 1.5 }

• Potential flow around a thin plate

  Solid (cube(0,0,0,0.5)) { sy = 0.06251 tx = 0.031249 ty = -0.015 }

• Geostrophic adjustment

  Solid (z + H0)

• Geostrophic adjustment on a beta-plane

  Solid (z + 1.)

• Coastally-trapped waves

  Solid (union (- ellipse (0, 0, 0.49975, 0.49975), z + 1.))

• Coastally-trapped waves with adaptive refinement

  Solid (union (- ellipse (0, 0, 0.49975, 0.49975), z + 1.))

• Gravity waves in a realistic ocean basin

    Solid bath.gts

• Parabolic container with embedded solid

    Solid ({
	    double line1 = SLOPE*x - y + 28000./pow(2.,LEVEL);
	    double line2 = - SLOPE*x + y + 28000./pow(2.,LEVEL);
	    return union (line1, line2);
	    })

• Tsunami runup onto a plane beach

    Solid (y - 60000.*(0.5 - 0.99/pow(2,LEVEL)))

• Lake-at-rest balance in an inclined domain with cut cells

    Solid (sphere(5.,0.,0.,2.0))

• Creeping Couette flow between eccentric cylinders

  Solid (- ellipse (0.,ECC,R2,R2))

  Solid (ellipse (0.,0.,R1,R1))

• Flow between eccentric cylinders on a stretched grid

  Solid (- ellipse (0.,ECC,R2,R2))

  Solid (ellipse (0.,0.,R1,R1))

• Balance with solid boundaries

    Solid (-y + 0.3)

    Solid ( y + 0.2)

• Simple example of groundwater flow following Darcy's law

    Solid (-difference(ellipse(0,0,0.7,0.7), ellipse(0,0,0.3,0.3)))

• Groundwater flow with piecewise constant permeability

    Solid (-difference(ellipse(0,0,0.7,0.7), ellipse(0,0,0.3,0.3)))