One of the major developments is the particle model, which has been significantly improved and expanded in FLOW-3D v11.2.

In the new model, particles are grouped into the following classes based on their primary functionality:

• Marker particles are simple, massless markers, best used for tracking fluid flow
• Mass particles represent solid objects such as sand grains or inclusions
• Fluid particles are made up of fluid and inherit fluid properties, including solidification
• Gas particles represent bubbles that change their size in response to temperature and pressure loads from the surrounding fluid
• Void particles are similar to the gas particles but their specific function is to represent and track collapsed void regions, which is useful, for example, to predict potential porosity defects created during mold filling in casting
• Mass/momentum source particles represent user-defined mass/momentum sources in the mesh
• Probe particles act as diagnostic devices that record and report solution quantities at their locations; they can be made of particles of any other class
• User particles can be customized through user-defined functions in the source code

Read the full blog post about mass particles at https://www.flow3d.com/mass-particles-and-acoustop horetics/