case.sif

!---------------------------------------------------------------------------
! Simple channel flow to test the implicit friction law where
! drag force is relative to normal force with a user specified coefficient.
! Here upper wall uses slip coefficient and lower wall friction coefficient. 
!
! P.R. 25.3.2022
!---------------------------------------------------------------------------


$ v0 = 1.0
$ slipc = 10.0
$ fricc = 5.0

Header
  CHECK KEYWORDS Warn
  Mesh DB "." "rect"
  Include Path ""
  Results Directory ""
End

Simulation
  Max Output Level = 7
  Coordinate System = Cartesian
  Simulation Type = Steady State
  Steady State Max Iterations = 1

  Output Intervals = 0
  Post File = case.vtu
  Set Dirichlet BCs by BC Numbering = True
  Initialize Dirichlet Conditions = False
End

Constants
  Gravity(4) = 0 -1 0 9.82
  Stefan Boltzmann = 5.67e-08
  Permittivity of Vacuum = 8.8542e-12
  Boltzmann Constant = 1.3807e-23
  Unit Charge = 1.602e-19
End

Body 1
  Target Bodies(1) = 1
  Name = "Body 1"
  Equation = 1
  Material = 1
  Initial Condition = 1
  Body Force = 1
End


Initial Condition 1
  Velocity 1 = 1.0e-6
  Velocity 2 = 0.0
End 

Body Force 1
  Flow BodyForce 2 = -10.0
End 



Solver 1
  Equation = Navier-Stokes

  Procedure = "FlowSolve" "FlowSolver"
!  Procedure = "IncompressibleNSVec" "IncompressibleNSSolver"
 
  Stabilization Method = Stabilized

  Steady State Convergence Tolerance = 1.0e-5

  Nonlinear System Convergence Tolerance = 1.0e-6
  Nonlinear System Max Iterations = 30

! activates also the newtonian linearization of viscosity
  Nonlinear System Newton After Iterations = 5
  Nonlinear System Relaxation Factor = 1
  Nonlinear System Newton After Tolerance = 1.0e-3

  Linear System Solver = Iterative
  Linear System Symmetric = True
  Linear System Iterative Method = BicgstabL
  BiCGStabl polynomial degree = 4
  Linear System Max Iterations = 500
  Linear System Convergence Tolerance = 1.0e-10
  Linear System Residual Output = 10
  Linear System Preconditioning = ILU2

  Calculate Loads = True
  Implicit Friction Exclude Pressure = Logical True


End


Equation 1 :: Active Solvers=1

Material 1
  Density = 1.0
  Viscosity = 1.0
End


Boundary Condition 1
  Target Boundaries(1) = 2
  Name = "Right"
  Velocity 2 = 0.0
End

Boundary Condition 2
  Target Boundaries(1) = 4
  Name = "Left"
  Velocity 1 = Variable "Coordinate 2"
    Real MATC "4*tx*(1-tx)*v0"
  Velocity 2 = 0.0
End

Boundary Condition 3
  Target Boundaries(1) = 1
  Name = "Bottom"
!  Velocity 1 = 0.0
!  Slip Coefficient 1 = $slipc
  Implicit Friction Coefficient = Real $fricc
  Velocity 2 = 0.0
End

Boundary Condition 4
  Target Boundaries(1) = 3
  Name = "Top"
!  Velocity 1 = 0.0
  Slip Coefficient 1 = $slipc
!  Implicit Friction Coefficient = Real $fricc
  Velocity 2 = 0.0
End


Solver 1 :: Reference Norm = 4.50911443E-01