• Solver Fortran File: GlaDSCoupledSolver.F90 and GlaDSchannelSolver.F90
• Solver Name: GlaDSCoupledSolver, GlaDSsheetThickDummy and GlaDSchannelOut
• Required Output Variable(s): Hydraulic Potential, Sheet Thickness and Channel Area
• Required Input Variable(s): None
• Optional Output Variable(s): Vclose, Wopen, Water Pressure, Effective Pressure, Sheet Discharge, Sheet Storage and Channel Flux
• Optional Input Variable(s): Zb

The complete description of the equations solved by the GlaDS solver can be found in Werder et al. (2013). The implementation follows exactly these equations, except that optionally the hydraulic potential can be computed at the top of the water sheet instead than at the bed (keyword: Neglect Sheet Thickness in Potential).

The GlaDS solver solves for the hydraulic potential, the water sheet thickness and the cross-sectional area of the channels. Whereas the two first variables are nodal variable and define continuous fields, the Channel area is a discrete field only defined on the edge of the elements.

The GlaDS model is composed of three solvers:

• GlaDSCoupledSolver is the main solver and couple the solve of the 3 main variables Hydraulic Potential, Sheet Thickness and Channel Area. Detail on the keywords for this solver are given below.
• GlaDSsheetThickDummy is just a solver to declare the Sheet Thickness variable as a primary variable.
• GlaDSchannelOut has two functions: declare that the Channel Area variable is an edge variable (Element = “n:0 e:1”) and create output vtk files for edge variables.

Currently (June 2017), GlaDSchannelOut doesn't support parallel simulation. These solvers only work in transient. They can be executed either on a 2d plane view mesh defining the bedrock or on the boundary of a 3d mesh. More details about the specificity of the solvers are given below.

The GlaDS solvers depend on a lot of physical parameters. The SIF example given here is from the test A1 of SHMIP. The main parameters to be defined in the Material section are:

An example using the GlaDS Solver can be found in [ELMER_TRUNK]/elmerice/examples/GlaDS.

The description of the GlaDS model is in:
Werder M.A., I.J. Hewitt, C.G. Schoof and G.E. Flowers, 2013. Modeling channelized and distributed subglacial drainage in two dimensions. Journal of Geophysical Research: Earth Surface, 118(4), 2140-2158.