EDEM API Contact Model | Override particle velocity

MQ

Hello,

Is there any way/workaround to override particle velocity (and set to 0) in custom contact model API?

The idea is that when the two interacting particles (with initial attractive force) reach a certain overlap, they should abruptly stop (i.e. their velocities being instantaneously set to 'zero'), rather than applying decelerating/viscous force?

Simply setting contactResults.normalForce = zeroVector only removes acceleration between the particles, but they continue to move and further overlap with inertia (or last velocity).

Thank you.

Best regards,

MQ

RWood

Hi,

You've probably realised that you can't set the particle velocity directly as it's part of the protected data. The way I've done this in the past is to apply a force in a particle body force plugin that takes the current particle velocity and applies a counteracting force based on that.

results.force -= {
particle.mass* particle.velocity.getX() / timeStepData.timeStep,
particle.mass* particle.velocity.getY() / timeStepData.timeStep,
particle.mass* particle.velocity.getZ() / timeStepData.timeStep};

Simple, but it worked in my case (see attached). Ignore the random velocity directions, that was something unrelated.

Cheers,

Richard

RWood

Hi,

You've probably realised that you can't set the particle velocity directly as it's part of the protected data. The way I've done this in the past is to apply a force in a particle body force plugin that takes the current particle velocity and applies a counteracting force based on that.

results.force -= {
particle.mass* particle.velocity.getX() / timeStepData.timeStep,
particle.mass* particle.velocity.getY() / timeStepData.timeStep,
particle.mass* particle.velocity.getZ() / timeStepData.timeStep};

Simple, but it worked in my case (see attached). Ignore the random velocity directions, that was something unrelated.

Cheers,

Richard

jpmorr

You could probably achieve this by using a particle body force model in conjunction with the contact model. Set a custom property to mark the particles that require a reset in the contact model and then set to zero with the particle body force. Works quite well.