Add the script to Simulation Flow (Ctrl/Cmd + F2) > StepsPre.
The script deletes particles from a Dyverso domain ("DY_Domain01") when velocity is greater than a random value between 7.0 m/s and 9.0 m/s:
import random
dyversoDomain = scene.get_DY_Domain("DY_Domain01")
particles = dyversoDomain.getParticles()
velocityMin = 7.0
velocityMax = 9.0
for particle in particles:
particleVelocity = particle.getVelocity().module()
randomLimit = random.uniform(velocityMin, velocityMax)
if (particleVelocity >= randomLimit):
dyversoDomain.removeParticle(particle.getId())