Particle placement inside the model

Hello! We are unable to add the particle in that small circle inside this picture in solution feilds under simulation runs.
We have tried to add it using hide selection, but it seems like it doesn’t work. Any help as soon as possible would be appreciated…
Here’s the pic:

Hello, could you please provide the project link as well? Otherwise we are not sure exactly what project you are referring to.

Thanks!

I am sorry for the late reply, but here we are unable to choose a particle point inside the model. We have a small cough opening(small circle on a block) that we need to assign a particle to.

Hello - this link doesn’t seem to work for me. I believe this project has been deleted.

Cheers

I believe this should work.

Thanks for the link.

Firstly, the workflow to select that as a seed face for the traces is to hide one of the external faces:

And this will let you to select the small face for the traces:

However, as you can see, in this case we don’t have any traces coming from there for a very simple reason. This simulation that you are running is a steady-state analysis (and not transient):

The simulation is running for 1000 iterations. The cough is only being applied between iterations 0 and 10 with a ramp:

In short, after iteration 10, there is no cough anymore, therefore you would never be able to generate traces with these settings. As you seem to be interested in transient analysis, I would highly recommend that you extensively read/watch/research for set up information on this topic, since transient analysis are much more costly.

This webinar is a good starting point.

Cheers

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Thank You so much for your reply. That made so much sense. I am actually not aware of the transient state and the steady state. A group member might have taken it from somewhere. Would you recommend just inputting the velocity would be enough for constant flow of cough?

As in, defining a fixed flow rate for the cough and assuming a steady-state analysis? This is naturally an approximation, but it should give you a very rough idea of the system (obviously no one coughs/exhales continuously).

In terms of complexity, it’s much easier/quicker to run steady-state, instead of transient analysis.

Cheers

Hi! I have a quick question about the flow for the same project. I noticed that inlet 2 was not generating flow line after a certain amount of time. I think this is happening with the cough outlet as well. Do you know what could be the problem with that?
Thank You so much for your help.
Screen Shot 2021-04-14 at 4.38.45 PM

Hi there, it seems that both of the inlets are generating streamlines:

What surface did you place your seed face on?

Best regards,
Fillia

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Thanks for your reply, Ms. Filia. I placed my particles on each of the inlets, and also on the cough inlet. But, I was not able to see the flowline after certain seconds for the cough inlet and the other inlet. Also, I reduced both vertical and horizontal seeds to 1. And this is the image after running for 1000 seconds! This is the same that’s happening with the cough inlet as well. Is there any way we can generate complete flowlines for each if the inlets?

Hi,

To me it’s also working as expected:

I only find unusual the volumetric flow rate for your cough, which is generating velocities of around 700 m/s in the domain:

Cheers

By the way, reducing both horizontal and vertical seeds to 1 will visualize a single stream. If you had both of them set to 2, you would get 2*2=4 streams.

Thank You so much. That makes so much sense now. I had a couple other questions with the simulation as well.

  1. For the same model, we had some pressure outlets as well. But, when I put a particle on my cough inlet, the cough particles were not even touching my pressure outlet. Do you think if there is any problem with our inlet and outlet understanding, or is there any problem with the model itself?

2)Also, I was wondering if we had any way to calculate the percentages for different particles in a particular volumetric space? I am asking this because we are going to compare different models with different cough locations, so what according to you would be the best metrics (aka a measurement of differentiation among those models)? Like what would you recommend to use to compare among several different models?

Thank You so much for your support.

Or of we could compute some sort of volumetric analysis on the models? Like so and so percentages of a particular type of particle and so on. Is there any way we can do this in SimScale?