It's a pipe filled with water (actually I'm using the "cylinder_in_channel.iges" from the Elmer samples directory) with:

- a no-slip boundary condition on side walls and the square obstacle (Boundary Condition 1)

- no boundary conditions on inlet and outlet faces

- a body force along the axis of the pipe

and I'm aiming for a steady state solution with the Navier-Stokes and K-Epsilon solvers

I think I'm missing something obvious, but I can't find what is it.

Here my .sif file:

- Code: Select all
`Header`

CHECK KEYWORDS Warn

Mesh DB "." "."

Include Path ""

Results Directory ""

End

Simulation

Max Output Level = 5

Coordinate System = Cartesian

Coordinate Mapping(3) = 1 2 3

Simulation Type = Steady state

Steady State Max Iterations = 1

Output Intervals = 1

Timestepping Method = BDF

BDF Order = 1

Solver Input File = case.sif

Post File = case.ep

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

Body Force = 1

End

Solver 3

Equation = K-Epsilon

Procedure = "KESolver" "KESolver"

Exec Solver = Always

Stabilize = True

Bubbles = False

Lumped Mass Matrix = False

Optimize Bandwidth = True

Steady State Convergence Tolerance = 1.0e-5

Nonlinear System Convergence Tolerance = 1.0e-7

Nonlinear System Max Iterations = 20

Nonlinear System Newton After Iterations = 3

Nonlinear System Newton After Tolerance = 1.0e-3

Nonlinear System Relaxation Factor = 1

Linear System Solver = Iterative

Linear System Iterative Method = BiCGStab

Linear System Max Iterations = 500

Linear System Convergence Tolerance = 1.0e-10

BiCGstabl polynomial degree = 2

Linear System Preconditioning = Diagonal

Linear System ILUT Tolerance = 1.0e-3

Linear System Abort Not Converged = False

Linear System Residual Output = 1

Linear System Precondition Recompute = 1

End

Solver 2

Equation = Navier-Stokes

Procedure = "FlowSolve" "FlowSolver"

Variable = Flow Solution[Velocity:3 Pressure:1]

Exec Solver = Always

Stabilize = True

Bubbles = False

Lumped Mass Matrix = False

Optimize Bandwidth = True

Steady State Convergence Tolerance = 1.0e-5

Nonlinear System Convergence Tolerance = 1.0e-7

Nonlinear System Max Iterations = 20

Nonlinear System Newton After Iterations = 3

Nonlinear System Newton After Tolerance = 1.0e-3

Nonlinear System Relaxation Factor = 1

Linear System Solver = Iterative

Linear System Iterative Method = BiCGStab

Linear System Max Iterations = 500

Linear System Convergence Tolerance = 1.0e-10

BiCGstabl polynomial degree = 2

Linear System Preconditioning = Diagonal

Linear System ILUT Tolerance = 1.0e-3

Linear System Abort Not Converged = False

Linear System Residual Output = 1

Linear System Precondition Recompute = 1

End

Solver 1

Equation = Result Output

Output Format = Vtk

Procedure = "ResultOutputSolve" "ResultOutputSolver"

Output File Name = case

Exec Solver = Always

End

Equation 1

Name = "FluidEquations"

Active Solvers(3) = 3 2 1

End

Material 1

Name = "Water (room temperature)"

Viscosity Model = K-Epsilon

Viscosity = 1.002e-3

Heat expansion Coefficient = 0.207e-3

Heat Conductivity = 0.58

Relative Permittivity = 80.1

Sound speed = 1497.0

Heat Capacity = 4183.0

Density = 998.3

End

Body Force 1

Name = "BodyForce 1"

Flow Bodyforce 1 = 1

End

Boundary Condition 1

Target Boundaries(1) = 2

Name = "wall"

Normal-Tangential Velocity = True

Noslip wall BC = True

End

If someone can point me any suggestion or problem in the sif file, it would be infinitely appreciated.

Thanks to the Elmer Team and all contributors for providing this beautiful piece of free software ♡＾▽＾♡