[Venky_94]

I'm running a simple bubble growth case, which is running perfectly fine without the dynamic mesh refinement. I'm using a grid size of 0.02*0.02mm generated by blockMesh for the simulation.

I've adaptive time stepping turned on with a maxCo set at 0.5, while running with the dynamicMeshDict, I'm noticing that the deltaT starts dropping drastically after a point (upto 1e-53 or 1e-119) and the program crashes with floating point exception error. Also even while the program is running normally, the deltaT is much higher than a much finer grid (around 2 e-7).

I've run with a fine grid of 0.01*0.01mm generated by blockMesh without dynamic mesh and it's running perfectly fine, and the average deltaT is also higher (around 2e-6).

I'm sharing my dynamicMeshDict here. I'd really appreciate if someone could share their inputs. I see that a lot of them are facing the same issue with dynamic mesh refinement but there has been no resolution posted.

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  9
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    format      ascii;
    class       dictionary;
    location    "constant";
    object      dynamicMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dynamicFvMesh   dynamicRefineFvMesh;

// How often to refine
refineInterval  5;

// Field to be refinement on
field           alpha.water;

// Refine field in between lower..upper
lowerRefineLevel 0.001;
upperRefineLevel 0.999;

// If value < unrefineLevel unrefine
unrefineLevel   0.001;

// Have slower than 2:1 refinement
nBufferLayers   3;

// Refine cells only up to maxRefinement levels
maxRefinement   1;

// Stop refinement if maxCells reached
maxCells        250000;

// Flux field and corresponding velocity field. Fluxes on changed
// faces get recalculated by interpolating the velocity. Use 'none'
// on surfaceScalarFields that do not need to be reinterpolated.
correctFluxes
(
    (phi none)
    (nHatf none)
    (rhoPhi none)
    (alphaPhi0.water none)
    (ghf none)
);

// Write the refinement level as a volScalarField
dumpLevel       true;


// ************************************************************************* //

[al.csc]

Simple guess: are you running a 3D refinement in a 2D case?