The Saffman formulation for lift force is applicable to inertial particles in a shear flow that are an appreciable distance away from boundaries. Two different formulations of the lift force are available: Saffman and Wall induced. The drag force acts in parallel with the fluid velocity with respect to the particle, whereas the lift force typically acts normal to it. Lift forces are relevant when particles move in a nonuniform fluid velocity field. The distribution of particle velocity directions has been left unchanged it is an isotropic circle for both releases.Ī dedicated Lift Force feature is now available for the Particle Tracing for Fluid Flow interface. Particles with uniform speed (left) or a pseudorandom distribution of different speeds (right).

This latter additional feature is activated in the Advanced Settings section by selecting the Subtract moving frame velocity from initial particle velocity check box. Particle tracing in rotating frames allows for easier modeling of particle motion in rotating machinery, such as mixers and turbomolecular pumps, because the particle trajectories can be computed in a frame of reference that is attached to the moving geometry.īy adding this feature to a model, release-based features will include an option to specify whether the initial particle velocity is defined with respect to the rotating frame or with respect to the inertial (nonrotating) frame. When you specify the center of rotation, direction of rotation, and angular velocity magnitude of the frame, the centrifugal, Coriolis, and Euler forces that are exerted on the particles are automatically applied. The Rotating Frame feature in particle tracing is now available for rotating frames of reference. Particles, colored by their unique particle index, traveling through a domain with sector symmetry.

Particle tracing module comsol 5.3