{"id":166019,"date":"2022-02-01T18:16:50","date_gmt":"2022-02-01T18:16:50","guid":{"rendered":"\/forum\/forums\/topic\/how-to-avoid-vacuum-effect-at-the-inlet-and-outlet\/"},"modified":"2022-02-11T15:31:39","modified_gmt":"2022-02-11T15:31:39","slug":"how-to-avoid-vacuum-effect-at-the-inlet-and-outlet","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/how-to-avoid-vacuum-effect-at-the-inlet-and-outlet\/","title":{"rendered":"How to avoid vacuum effect at the inlet and outlet?"},"content":{"rendered":"
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Hi,<\/p>\n

I try to simulate a coughing scenario with inert particles using DPM and multiphase flow and its interaction of particles with the human face directly at the opposite side of the coughing mouth (inlet) as given in the figure below. I also defined another inlet (room_inlet) which is the surface where the inlet is located to simulate a constant room airflow in the room in the same direction with the cough. So, when there is no airflow from the room_inlet, it is fine. But when the room_inlet has a value larger than 0, e.g., 1 m\/s, the emitted particles flow back to the inlet (mouth) as if there is a vacuum. So this is the first problem.<\/p>\n

The second problem is similar. When I define the outlet which is the circular surface (human face) as the pressure outlet., the particles in the vicinity of the outlet are absorbed as if there is a vacuum in the outlet. All of the initial\/gauge pressures are 0 Pa. Basically, I count the particles that is trapped at the outlet.<\/p>\n

So, is the problem about the pressure values, inlet\/outlet types or anything else?<\/p>\n

Thank you for your help in advance, <\/p>\n

Fatih<\/p>\n

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