[teuton]

Hello all. In my case, there is a chimney that disperses pollutants to open atmosphere( enclosure). It is velocity boundary condition. How can I calculate some paramters such as turbulence characteristic length or hydraulic diameter?

Regards,

[bpulat]

Hello teuton,

I highly recommend you to do a quick research before asking a question for the next one.
For your question https://www.cfd-online.com/Wiki/Hydraulic_diameter check out this link. I think you will understand what to do with hydraulic diameter and turbulence length scale.
To calculate hydraulic diameter you should use the dimension of your enclosure and then using hydraulic diameter to calculate your turbulence length scale. Don't forget that this turbulence length scale is an estimation for fully developed inlet boundry condition.

I also want to note that depending on your boundry conditions a vortex shedding can happen behind your chimney. So if needed adding helical strakes to the chimney can be handy for your design.

Best Regards,

Baris

[teuton]

Hello Baris,

Thank you for reminding me very basics of fluid mechanics, but my concern is about modelling atmospheric boundary layer.

Anyway, I found what I was looking for. I suggest everyone who wants to model atmospheric bc. to read Bert Blocken and P.J. RICHARDS's articles.

Regards,

[bpulat]

Hello teuton,

In my case, there is a chimney that disperses pollutants to open atmosphere( enclosure). It is velocity boundary condition. How can I calculate some paramters such as turbulence characteristic length or hydraulic diameter?

With limited information about what you really need. And regarding to your question i think the answer is proper.

Regards,

Baris