Hi everyone,

I want to know which particle escaped from the domain. But I cannot find the way to see each particle fate. I am using "file" as injection type. I have to inject a lot of particles. Maybe I can know which particle escaped if I use "single" as injection type. But this is going to be hard because of the number of particles.

Does anyone know how I can know each particle fate?

Regards, AKR

It is possible to write a UDF which can be applied at a specific boundary (i.e. outlet) to keep track of which particles escape. If you have some experience with UDFs, you could probably write something to do this in about a week.

Otherwise, you can just visualize the particles by injection number or initial position or other parameter, and then see how this matches with the number of particles that escape with Fluent's standard text reporting.

Hi Allan,

I have some experiences with UDFs. So far I am thinking about using DEFINE_DPM_OUTPUT. This may work for me. But I am not sure. Have you ever written DEFINE_DPM_OUTPUT? If so, could you tell me about this? I have read udf manual of fluent, but there is no detail about it. Or I can also use step by step report in particle track panel.

Do you have any suggestion?

Thanks, AKR

I have used DEFINE_DPM_BC applied to an outlet boundary condition. This allows for access to the particle state and other information such as the particle ID when the particles reach the outlet (or other specified boundary).

It looks like DEFINE_DPM_OUTLET could work also - it is described in the manual. You need to decide what you really need, and perhaps the built-in tracking would be more cumbersome but would still work. If you are using this for a single problem only, I would not recommend writing a UDF.