Learning Forum

[ebochi]

Hi. I'm trying to study the oscillation angle of a fluid vibrator.

And, I have actual research data through wind tunnel experiments.

Based on the data, the time step and inlet pressure are set to proceed, but the oscillation dosen't continue.

The settings are, (Pressure inlet - 340 kPa(gauge)) / (time step - 1/8 cycle for real freqyency) / (k-epsilon 2eqn & Coupled methods & Air for ideal gas, sutherland's law) / (Hybrid initialize)

total 1 milion fluent mesh, Most mesh inside the fluid vibrator, Others, it was distributed appropriately.

Sometimes, I have to make the time step very large so it oscillate, I don't know what's wrong.

Please advise. Thx.

[Federico]

Can you try initializing from the inlet?

[ebochi]

yes, I tried to initialize from the inlet, with both two options. 

and the worst result was obtained. 

[Federico]

Hard to tell from this information alone.

You might need to reduce the time step further (we typically recommend 20 time steps to capture oscillations) to temporally resolve the perturbations that initiate the feedback loop.