wrong particle trajectory (DPM)


I am new here so please correct me if I am doing something wrong.

I am trying to simulate the water spray of a tire on a wet road (my problem appears at the bow wave). To do that I inject water from a surface of the moving tire wall into the air stream (25 m/s). The problem is that the particles are not getting ejected into the right direction. 

They should be ejected in to the direction of the red arrow and then get redirected by the air stream.

These are the velocities at the tire wall.

Making the tire wall stationary does not help. What is funny is that I first got the "right" solution for the trajectories and then it suddenly became false then after some time I got the right solution again and now it is false again (without really changing the setup). 

Reloading or completely reseting the simulation and setting it up again did not help as well. 

I am fairly new to CFD so it is probably some dump mistake. 

Please let me know if you need more information.

Thank you very much in advance. 


  • DrAmineDrAmine GermanyForum Coordinator
    edited August 2019

    Are you using  MRF approach for wheel rotation? Check the Consideration in the manual when one wants inject particle from a surface which is supposed to rotate. Can you check if you are tracking in relative frame? 

  • Ace993Ace993 Member
    edited August 2019


    thank you for your time!

    No, the wheel is just a moving wall.

    Tracking in relative or absolute frame does not make a difference (tried it). Do you think I need to consider the tire velocity in the injection velocity? 

  • DrAmineDrAmine GermanyForum Coordinator
    edited August 2019

    Yes: You need to consider that in your injection. Best to write an injection file for that to have the tangential velocity of particles on entrance into the domain.

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