[neko2650]

Hello,


I want to provide displacement at each time step through 6DoF.dat file where the I tried to control the solver to stop at each time step in controlDict file

startFrom       latestTime;
stopAt          nextWrite;

My basic Idea is stop the solver and edit the displacement in input 6DoF.dat file.
Initially I provided displacement in 6DoF.dat file for the first time step 0.01 and run the interFoam solver
(Here displacement is taken as a linear oscillating motion in y-direction)

2001      
(      
(0 ((0 0 0) (0 0 0)))
(0.01 ((0 0.016 0) (0 0 0)))
(0.02 ((0 0 0) (0 0 0)))
(0.03 ((0 0 0) (0 0 0)))
(0.04 ((0 0 0) (0 0 0)))
(0.05 ((0 0 0) (0 0 0)))

and the consecutively the displacement is updated at each time step

(0.02 ((0 0.033 0) (0 0 0)))

so on and so forth

When I tried to plot the force output shown in figure 1 it had local maxima and minima points (which are of no engineering importance). For comparison when I used the linearOscillating function in dynamicMeshDict file it provided me with a smooth plot shown in figure 2. Also figure 3 shows detailed comparison.

Also I noticed that when I provide two displacement values (i.e current and next time step values) to solve for the current time step values the force values obtained again looks similar to oscillatingLinear function

My query is how do I determine the input values which OpenFoam takes to provide mesh motion and calculate the forces at a given time step.
Does it has something to do with ddtScheme (explicit/implicit) I am using Euler
or it is related to dynamicMotionSolverFvMesh. I checked with both displacementLaplacian and solidBody motion solver or Is it something more which I haven't considered yet.

Kindly Help!


Thanks in advance