GfsMetricStretch

From Gerris

GfsMetricStretch is used to stretch the mesh uniformly in one or several directions of space.

The syntax in parameter files is:

[ GfsEvent ] { sx = 2. sy = 0.1 sz = 1. }

where (sx,sy,sz) are the factors by which the x,y and z directions of space get rescaled.

Note that the geometric multigrid Poisson solver native to Gerris might struggle when the aspect ratio of the cells becomes large (typically > 5). For high aspect ratios, you can try to use the algebraic solvers of the Hypre library via the Hypre module.

Examples

• Lid-driven cavity on an anisotropic mesh

  MetricStretch {} { sy = 0.5 }

• Coriolis formulation in 3-D

  MetricStretch {} { sy = 0.5 sz = 0.25 }

• Wind-driven lake

    MetricStretch {} { sy = 0.1 }

• Flow between eccentric cylinders on a stretched grid

  MetricStretch {} { sy = 0.5 }