Reply To: How to simulate consumption of tracer during combined internal/external flow sim

[Rob]

If you use species as your tracer (water and water-tracer as an example) you also want inlet/outlets on the objects (mussels?). Look at expressions, so object-inlet just removes all mass and object outlet has an expression for species fraction that's (for example) [0.5 x inlet concentration]   Assuming the object in & out are matched then you can use velocity bc's on both surfaces and I'd use mass-weighted to find the species fraction on a flow boundary.