DPM simulation: When there is wind, the particles do not eject properly, how can I fix it?


I am very new to Ansys and I am trying to make a cough simulation and I want to add wind to my simulation, but when I add wind, the air goes into the mouth and prevents particles from ejecting.

Here is the result when there is no wind:

(The highlighted surface is the wind inlet, inlet velocity = 0)

And here are the results when there is wind:


(wind 🔝)

I have tried different wind velocities, but the result didn't change. I have tried to change the DPM setting for almost all surfaces, couldn't find a solution. Here is my setup:

Time: Transient

Gravity: -9.81 m/s^2

Energy: on

Species Transport: on

k-epsilon Model, Realizable

Discrete Phase settings:

-Interaction with continuous flow: on


--Injection 1 (surface)

---Material: mixture template

---Velocity: 10 m/s

---Start/Stop: 0-1 s

---Diameter: 5e-6 m (uniform)

---Mass flow: 5e-6 kg/s

---H2O mass fraction: 0.012

---Evaporating species: H2O

--Injection 2 (surface)

---Material: mixture template

---Velocity: 4.2 m/s

---Start/Stop: 0-1 s

---Diameter-> min: 77e-6m, max: 737e-6 m, mean: 170e-6 m

---Mass flow: 5e-6 kg/s

---H2O mass fraction: 0.012

---Evaporating species: H2O

Boundary Conditions

-Cough inlet:

Velocity: 10 m/s

DPM: escape

-Breath inlet

Velocity: -4.2 m/s

DPM: escape

-Wind inlet

Velocity: 4 m/s

DPM: escape

-Human models DPM: Trap

-Floor DPM: Trap

-Other surfaces DPM: Escape

Initialization: Hybrid


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