[saadbin]

Very sorry, I just updated the permission for the image, you can look at it now I hope.

[saadbin]

1. I tried the ‘gdb’ debugger to figure out the origin (see the image here: https://drive.google.com/file/d/1O99J2tEe6WEl2TNDuoLZmfluHS2hK1iv/view?usp=sharing). From what I understand from it, the scaling error is coming from the following line inside cylinder3d.cpp:

SuperLatticeYplus3D<T, DESCRIPTOR> yPlus( sLattice, converter, superGeometry, stlReader, 5 );

This is defined inside src/functors/lattice/turbulentF3D.hh, where line 87 calls the function ‘normalize’:

normal = util::normalize(normalTemp);

-which is throwing the assertion error. Could you let me know what this line is actually doing?
And if I modify this line to not normalize, what problems should happen with the physics, because if I change it to “normal = normalTemp;” the error is not thrown anymore.

2. Currently my N is relative to the width of the channel (136 micron), not the width of the obstacle (3 micron). I am setting width of channel as charactersitic length because I am targetting a specific Knudsen number (meanfreepath/charL). As mean free path of air is constant, I was thinking I have to fix the charL to achieve my target Knudsen number. Do you think this approach is wrong? What do you suggest otherwise?

Thanks!

[saadbin]

Correction in my question on the first point:
Is there any way to ‘INCREASE’ the time step hence the lattice velocity? And hence, make the time propagation faster?

[saadbin]

Adrian, thanks for the feedback.

It was actually a RAM issue, as the number of voxels was crossing 1e7. I previously set my domain size excessively high compared to the length scale. However, even after fixing that, I am getting another error. Please, see the snapshot of error message here:

https://drive.google.com/file/d/1cX0MzHUhEOSvmzRw0MHqFjfXqPuo6Ru8/view?usp=sharing

The log file is here: https://drive.google.com/file/d/1X57SFN4bG6WiuCvW0I5Wgyxo26_jqZEx/view?usp=sharing

Apart from the error, several key things to be concerned about for me:

1. My time step (del_t = 5.4803e-10) is very small, which I cannot control because it is automatically calculated based on relaxation time (0.53) and del_x = L/N = 9e-7 (because of very small characteristic length L = 136 microns and resolution N = 150). Consequently, my lattice velocity(U*del_t/del_x) is verysmall at Re=0.1, where U = Re*viscosity/L = (0.1*1.5e-5)/(136e-6). Is there any way to reduce the time step hence the lattice velocity? And hence, make the time propagation faster?

2. My case is similar to the cylinder3d case, the difference is instead of a single cylinder at the center, I have a bunch of small cylinder-like structures on the floor with an approximate diameter of 3 microns each, where my channel dimension is about 400*136*136 micron^3. In my understanding, the resolution needs to be big to resolve the structures on the floor. So I set N=150. Let me know if my understanding is incorrect about the resolution requirement. A snap of the geometry is here: https://drive.google.com/file/d/1DDSyMybGBFhPVx3mRCz-JDyS4x1iAMHY/view?usp=sharing

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