Custom Boundary Condition - Actuator Disk Pressure Rise

Project Support
1

I’m modelling an engine using the custom boundary condition. I have an actuator disk modelled as shown in the image below where I want to apply a pressure rise of 360.54Pa.

Screenshot 2022-03-29 at 15.26.46
Screenshot 2022-03-29 at 15.26.46876×634 482 KB

I’m not sure if I’m using the correct settings though, because if I set the BC to these settings:

Screenshot 2022-03-29 at 15.33.44
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I get an error that the custom boundary is incorrectly defined as shown below. It says that the wall function is used even though I have it set to full resolution.

Screenshot 2022-03-29 at 15.35.09
Screenshot 2022-03-29 at 15.35.091594×348 36.4 KB

I am following the custom boundary tutorial recommended in my previous post, but I’m unsure what causes this error. What I need is for the actuator disk to increase the pressure at every point however it seems that the way I defined it (zero gradient for turb. kinetic energy and specific dissipation type)affects the whole flow and results in extremely high pressure values.

Any help would be appreciated. Here’s the link to the project: SimScale

Kind Regards,

Jakub

2

Hello Jakub,

as you have mentioned the right approach for this would be to set this zero gradient, or a fixed value, instead of a full resolution BC.

Anyway, for your simulation, I would not suggest to us a BC, because this will mean that the face will be treated as only an outlet. And not as a pressure jump interface as you want to use it.

What you’ll need to use is either momentum or a power source.

Best regards Sebastian