Zone based resolution

Dear DSPH

Is there any way to vary resolution? for zones or around objects or both? similar to meshing in CFD.

My results are not accurate due to insufficient resolution achievable, I believe. If these features are not in the current version but are in development, I would be interested to participate in moving this forward.

For larger simulations, either I'm doing something wrong or it's very hard to get good resolution without truly massive computing power needed.

• Not possible easily. Perhaps look at this thread:

https://forums.dual.sphysics.org/discussion/2200/drawpoints-at-exact-location#latest

Allows you to place particles exactly where you want. You would have to write some script to generate the geometry your self.

Also note this does not alter smoothing length in any way, you are using uniform smoothing length every where using DualSPHysics right now.

Kind regards

• Great thanks!! That certainly looks interesting. I will take a look to see if I can get it working this weekend.

• Great to hear, looking forward to see what you come up with (if you decide to share, which is totally your own decision).

If you want to be fancy try googling "SPH particle packing" and you will see a few algorithms for "smartly" redistributing points in a geometry, but as usual, always best to use the simplest solution first :-)

Kind regards

• Happy to share my use case, just not sure it's that interesting from an academic perspective.

I'm designing a sailboat for offshore racing, for a specific race in the north ocean, where swell is a large factor... (also the potential of breaking waves although rare) why not simply use the empirical formulas out there? because it's a multi-hull with an asymmetric design and breaks all the normal "rules", and adding foils complicates things a bit.

What intrigued me about DSPH is the potential to work out the trim & balance of the vessel in swell (which is very important for performance) over the various points of sail, as many of the forces shift around with the sails. The mooring functionality is interesting as I can apply a counterforce at points and test out the limits of flying a hull and importantly in wave states. (swell is an important factor in offshore racing)

I can apply general physics to calculate static stability but dynamic stability is a different story. For cruising boats, we just apply a large safety factor. For racing, however, we want to get closer to reality and learn true limits in specific sea states.

Also this will be a fast boat possibly planing or semi-planing hull sections may add performance or be too draggy at low speeds. Hull steps may help, but enough? etc. etc.