Granular question

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Ruediger Mach
Posts: 2
Joined: Mon Mar 30, 2020 1:56 pm

Granular question

Post by Ruediger Mach » Mon Mar 30, 2020 2:06 pm

Hi everyone,
Description: I have a dam, made of sand which I want to interact with a fluid.
And I want to keep the dam's shape until the fluid touches it... trying to simulate the erosion.
There are two domains - one for the granular and one for the fluid and the interaction works perfect, but...
The dam doesn't keep its shape. It starts reacting on the gravity as soon as the sim starts.
I tried all kind of parameters to keep the dam in shape as long as it takes until the water get's in touch.
Domain granular parameters:
Res 1000
Density 1000
Interprenetation 1
Friction 0.7
St. Friction 0.9
Compactation 0.25
Damping 3

Dyverso settings
Min and Max substeps 8
Iterations 40

I want to be the sand stable like wet sand and only reacts on the fluid... any ideas?

Thank you very much

Christian Zuppinger
Posts: 24
Joined: Wed Jul 11, 2018 9:32 am

Re: Granular question

Post by Christian Zuppinger » Tue Mar 31, 2020 9:20 pm


the behavior of the granular solver is very much depending on the iterations of the simulation parameters. A higher number makes it more solid. You may need something like 400 instead of 40 iterations.
See this blog post ... n-dyverso/

Ruediger Mach
Posts: 2
Joined: Mon Mar 30, 2020 1:56 pm

Re: Granular question

Post by Ruediger Mach » Thu Apr 02, 2020 8:03 am

Hi Christian,
thank you very much - this helped. Increase the iterations up to 600 and the sim runs pretty well.
Found out that another trick helped - apart from being not physically correct....
Used different gravities for both domains... a regular one for the fluid and and reduced one for the granular domain... combined with an animated curve to change the gravity for the granular domain to 9.81 at that point when the fluid touches the sand ...


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