Subgrid for Acoustic Simulation, to limit grid size?

Hello,

Does the Acoustic Solver allow subgridding?

I'm trying to do acoustic ultrasound simulations in tissue/water, with air outside, for realistic reflections/interactions at the skin boundary.

The acoustic solver requires very high grid cell counts even for small objects. So far, setting the Background Material to Air, or including a surrounding object of air around the region of interest both increase the grid cell count by ~100x.

The outer air region is only to provide an impedence difference at the phantom/body boundary, to see reflections, so the resolution of the air volume is really not important, just the interaction at the air/body interface.

Is there any way to keep a reasonable grid size, either by subgridding, or voxel priority, or some other method?

Thank you!

There's no subgridding just a rectilinear / adaptive grid (you can create new grid settings and drag and drop solids or wireframes to these)

What you can do (at your own 'risk') is manually set the grid to the resolution you want and not use the automatic grid settings. Typically you want at least 10 points per wavelength (more is better) and the wavelength in air (343 / freq) and water (1500 / freq) are quite different.