[gill11a]

I am trying to implement electrostatic body force on dust particles in dpm. The particles have a charge and so does the boundaries. But the particle trajectory is such that the distance from boundaries is changing, hence the electrostatic force is changing. Is it possible to write such a udf that it changes the body force according to the particle trajectory.

[pakk]

Yes, and I have done so before. I can not give you that UDF because of confidentiality, but the essence:

*Calculate the gradients of the electric field with whatever method you want, and put them (using a defined-on-demand) into user defined memory, so that for each cell you know the gradients of the electric field.
*Write a dpm_body_force that uses the properties of the dust particle (mainly the charge) and the gradients in the cell that the dust particle is currently in to calculate the force (or actually acceleration) of the particle.

[gill11a]

Thanks a lot Pakk. Worked perfectly

[Mafinat0r]

Hey guys,

i read your thread here and have the same problem as gill11a got it six years bevor. I am complete new in Ansys Fluent, there i got no idea how to wirte an UDF-code.

In case you both are still active here it would be nice if you could contact me and send me your UDF-Code.

Best regards
manuel