hi, in my domain I have released x amount of water droplets and would like to compute how many particles that will hit a specified surface. is it possible for Fluent to calculate how many particles that will be trapped on surfaces?

Have you tried setting up DPM? Then set the boundary conditions so your specified surface is the only one labeled "trapped"

yes I have done the simulations and set the boundaries of interest to "trap". I should mention that I use "stochastic tracking" with the "discrete random walk method". after the iterations, may I compute which particles and how many that will hit the surfaces with BC set as "trap"?

Display > particle tracks

Make sure to have injections set up.

By the way, it takes a LONG time. parallel mode doesn't help speed it up. My advice is to not do "display" but just "track" because display will just take twice as long. Track will print out the results in your console.

Make sure ALL your walls are defined as 'Trap' in the DPM tab of the wall definition dialog.

the text command 'solve dpm' will run a dpm iteration.

the text command 'report dpm-summary' will print out a summary of results for the particles.

then I have another question: what's the difference between solving from >solve-iterate and tracking the particles from >display-Particle Tracks (in that menu I chose "track")? it seems to me that these two types of settings performs the same thing. or do they?