Particle – Wall Interaction

[Henderson_C]

Dear OpenLB commuminty,

I was wondering how OpenLB works with a moving solid particle interaction with fixed wall? In my simulations, once the particle collides with wall, it deforms and does not bounce back. In other words it sticks and it gets consumed by the wall. I am using bounce-back boundary conditions for the wall surface in OpenLB-1.5v.

Your response is appreciated.

[jan]

Dear Henderson,

As of OpenLB 1.5, no explicit particle-wall and particle-particle interactions are supported. All coupling is done through the fluid, but as you have noticed, this is not sufficient in many cases. That’s why we have developed a contact model that works for resolved convex particles (10.1016/j.partic.2022.12.005), which will be included in the next release.

Best regards,
Jan

[Henderson_C]

Dear Jan,

Its unfortunate to hear that. Is there a way to change the particle parameters such as the acceleration or the position during the simulations using a certain function?

Regards,

[jan]

Dear Henderson,

Yes, you can change all the fields provided by the PARTICLETYPE used. The following simple example iterates over all particles and gets and sets the position, velocity and force field. The latter corresponds to the acceleration of the particle according to Newton’s second law of motion.

constexpr unsigned D = 3; // or 2 depending on your setup
using namespace descriptors;

// Iterate over all particles
for(int iP = 0; iP < particleSystem.size(); ++iP) {
    // Get the particle
    auto particle = particleSystem.get(iP);

    // Get and set position
    Vector<T,D> position = particle.template getField<GENERAL,POSITION>();
    particle.template setField<GENERAL,POSITION>( position );

    // Get and set velocity
    Vector<T,D> velocity = particle.template getField<MOBILITY,VELOCITY>();
    particle.template setField<MOBILITY,VELOCITY>( velocity );

    // Get and set force
    Vector<T,D> force = particle.template getField<FORCING,FORCE>();
    particle.template setField<FORCING,FORCE>( force );
}

Best regards,
Jan

[Author]

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