Rob
Ansys Employee

OK, have a careful think about what you want. 

A cough is a transient event, but how far do you expect the "pulse" to travel, and for how long a duration will it move. Does that effect the overall room flow, do you need to include that effect in the model?

Particles tracked as "transient" will display as points (default) which tend to be near enough invisible. Have a look at spheres and scaling factors. 

 

Multiphase is a fun area: DrAmine and I have a fair bit of experience in that area. We (Ansys) sometimes split DPM from "multiphase" for historic reasons. Read the Theory Guide, and also look carefully at the range of the models and limitations.