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solvers:ssa [2013/12/10 08:54] gag [SIF contents] |
solvers:ssa [2017/05/19 05:20] (current) tzwinger [General Description] |
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==== General Informations ==== | ==== General Informations ==== | ||
- | :!: **Important changes have been made in '' | + | :!: **Important changes have been made in '' |
* **Solver Fortran File:** '' | * **Solver Fortran File:** '' | ||
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==== General Description ==== | ==== General Description ==== | ||
+ | |||
+ | === Ice flow === | ||
The '' | The '' | ||
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The '' | The '' | ||
- | Contrary to the NS solver, the gravity must be orientated along the z-axis and it taken form the value of | + | Contrary to the NS solver, the gravity must be orientated along the z-axis and is taken from the value of |
'' | '' | ||
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Note that in the absence of explicit boundary condition (no dirichlet condition or '' | Note that in the absence of explicit boundary condition (no dirichlet condition or '' | ||
- | Since version 6472, there are three friction laws implemented in the SSA solver: a linear friction law, a Weertman type friction law and a Coulomb type friction law. The two latests are non-linear and a Newton linearisation can be used. The friction law is chosen using the keyword '' | + | The SSA velocities and pressure can be used, for example, as initial conditions for the Stokes Solver. |
- | + | ||
- | The SSA velocities and pressure can be use, for example, as initial conditions for the Stokes Solver. | + | |
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* exported on the whole mesh using the '' | * exported on the whole mesh using the '' | ||
* used as a Dirichlet condition for the SIA velocity (see the [[solvers: | * used as a Dirichlet condition for the SIA velocity (see the [[solvers: | ||
+ | |||
+ | === Basal friction === | ||
+ | |||
+ | Since version 6480, there are three friction laws implemented in the SSA solver: | ||
+ | |||
+ | * a linear friction law | ||
+ | < | ||
+ | * a Weertman type friction law | ||
+ | < | ||
+ | * a Coulomb type friction law | ||
+ | < | ||
+ | where | ||
+ | < | ||
+ | and | ||
+ | < | ||
+ | |||
+ | The two latests are non-linear and a Newton linearisation can be used. The friction law is chosen using the keyword '' | ||
+ | * a linear friction law | ||
+ | * '' | ||
+ | * a Weertman type friction law | ||
+ | * '' | ||
+ | * '' | ||
+ | * '' | ||
+ | * a Coulomb type friction law | ||
+ | * '' | ||
+ | * '' | ||
+ | * '' | ||
+ | * '' | ||
+ | * '' | ||
+ | * '' | ||
+ | * '' | ||
+ | |||
+ | When < | ||
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SSA Mean Viscosity = Real $eta | SSA Mean Viscosity = Real $eta | ||
SSA Mean Density = Real $rhoi | SSA Mean Density = Real $rhoi | ||
- | |||
- | |||
- | |||
! Needed for Linear, Weertman and Coulomb | ! Needed for Linear, Weertman and Coulomb | ||
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! Iken's bound tau_b/N < C (see Gagliardini et al., 2007) | ! Iken's bound tau_b/N < C (see Gagliardini et al., 2007) | ||
SSA Friction Maximum Value = Real 0.5 | SSA Friction Maximum Value = Real 0.5 | ||
- | |||
End | End | ||
</ | </ | ||
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==== Examples ==== | ==== Examples ==== | ||
- | For examples look in your elmer source distribution under '' | + | For examples look in your elmer source distribution |