[MMatt]

I know that by using the "surface" type of injection, the number of parcels will automatically be equal to the number of cells in that surface, but due to my mesh being very refined on that surface, the number of parcels injected at every time step is huge (50'000).

Is there a workaround that issue? How can I reduce somehow the number of parcels injected?

Many thanks!

[vinerm]

There are at least two options - use group injection or use FILE injection. For FILE injection, setup the injection you already have and then sample the particles at the injection boundary. Now, open this file and edit it. During editing, you have to modify following

1. Number of parcels. Each line represents a parcel
2. Each parcel has mass of particle, mass of parcel, and number of particles represented by the parcel, given as frequency. You need to modify the mass of the parcel, shown as mass-flow-rate and the frequency since you are reducing the number of parcels.
3. Keep only as many lines as many parcels you want. So, if you want 5000, then remove 45000 lines. A good text editor would be very handy here.

Then, switch from surface injection to file injection and read this file.