i try to investigate the behaviour of an ALE-formulated fluid grid. I would like to know, how to work and how such a grid acts.
So in the given pdf & sif-file you see what I tryed to do:
I applied a flow on the left boundary and on the "top" of a block I applied a parameterized velocity, e.g. a Mesh-Update in a triangular shape.
I plotted the result, you can see the deformed shape of the grid. But I don´t understand why on the left side the node moves and why there is on pick in the middel.
I don´t understand this.
I tryed to do this on the top boundary and it worked. So why doesn´t it work on the block top side??
Has anyone an idea?
Denis
Code: Select all
Header
Mesh DB "." "fsi"
End
Constants
End
Simulation
Coordinate System = Cartesian 2D
Simulation Type = Transient
Steady State Max Iterations = 25
Steady State Min Iterations = 2
TimeStepping Method = BDF
BDF Order = 2
Timestep Sizes = 0.01
Timestep Intervals = 3
Output Intervals = 1
Output File = "fsi.result"
Post File = "fsi.ep"
End
Body 100
Equation = 1
Material = 1
End
Material 1
Density = 1.0
Viscosity = 0.5
Poisson Ratio = 0.3
End
!! FLUID
Solver 1
Equation = Navier-Stokes
Procedure = "FlowSolve" "FlowSolver"
Exec Solver = Always
Stabilize = True
Bubbles = False
Lumped Mass Matrix = False
Optimize Bandwidth = True
Linear System Solver = Direct
!Linear System Solver = Iterative
!Linear System Iterative Method = BiCGStab
!Linear System Preconditioning = ILU1
Linear System Max Iterations = 500
Linear System Convergence Tolerance = 1.0e-8
Nonlinear System Max Iterations = 50
Nonlinear System Convergence Tolerance = 1.0e-5
Nonlinear System Newton After Tolerance = 1.0e-5
Nonlinear System Newton After Iterations = 50
Nonlinear System Relaxation Factor = 1.0
Steady State Convergence Tolerance = 1.0e-6
End
!! MOVING MESH
Solver 2
Equation = Mesh Update
Variable = -dofs 2 Mesh Update
Exec Solver = Before Timestep
Linear System Solver = Direct
Linear System Preconditioning = ILU1
Linear System Max Iterations = 500
Linear System Convergence Tolerance = 1.0e-8
Steady State Convergence Tolerance = 1.0e-6
End
!! OUTPUT
Solver 3
Exec Solver = String "after timestep"
exec interval = 1
Equation = String "ResultOutput"
Procedure = File "ResultOutputSolve" "ResultOutputSolver"
Output File Name = String "plot_fsi."
Output Format = String "vtu"
Vtk Format = Logical False
End
!! OUTPUT BOUNDARY
Solver 4
Exec Solver = String "After Simulation"
Equation = "SaveLine"
Procedure = "SaveData" "SaveLine"
Filename = "boundary_values.dat"
End
Equation 1
Active Solvers(2) = 1 2
End
!---------------------------------------------------------------
! B O U N D A R Y C O N D I T I O N S
!---------------------------------------------------------------
Boundary Condition 1 !left handside boundary
Target Boundaries = 1
Velocity 1 = Variable Time
Real Procedure "FsiStuff" "InFlow"
Velocity 2 = 0.0
Mesh Update 1 = 0.0
Mesh Update 2 = 0.0
End
Boundary Condition 2 !rechter Rand
Target Boundaries = 2
Velocity 2 = 0.0
Mesh Update 1 = 0.0
Mesh Update 2 = 0.0
Pressure = 0.0
End
Boundary Condition 3 !boundary top & bottom
Target Boundaries = 3
Velocity 1 = 0.0
Velocity 2 = 0.0
Mesh Update 1 = 0.0
Mesh Update 2 = 0.0
End
Boundary Condition 4 ! block right & left handside
Target Boundaries (2) = 5 4
Mesh Update 1 = 0.0
Mesh Update 2 = 0.0
Velocity 1 = 0.0
Velocity 2 = 0.0
End
Boundary Condition 5 ! Block top
Target Boundaries = 6
Velocity 1 = Equals Mesh Velocity 1
Velocity 2 = Equals Mesh Velocity 2
Mesh Update 2 = Variable Coordinate 1
0 0.00
1 -0.02
2 -0.04
3 -0.06
4 -0.08
5 -0.1
6 -0.08
7 -0.06
8 -0.04
9 -0.02
10 0.00
End
Mesh Update 1 = Variable Coordinate 1
0.0 0.0
1.25 0.0
2.50 0.0
3.75 0.0
5.00 0.0
End
End