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#1 |
Super Moderator
Tobias Holzmann
Join Date: Oct 2010
Location: Bad Wörishofen
Posts: 2,712
Blog Entries: 6
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Dear community,
I published a new tutorial which is related to buoyancy driven flows. The training case includes the well known run script which will give you all information you need. The case is a solar chimney (imaginary case) in 3D. I simulated just one quarter of the whole design. The driving force in that tutorial is the buoyancy force. ![]() Video: https://www.youtube.com/watch?v=mYV18BMr8HY The can be downloaded from my website https://Holzmann-cfd.de
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Keep foaming, Tobias Holzmann |
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#2 |
New Member
Paul
Join Date: Nov 2017
Posts: 15
Rep Power: 9 ![]() |
Hello Tobias,
I want to ask 3 questions about the case please: 1) How did you estimate the mixingLength for k at the inlet in the initial conditions folder? PHP Code:
3) Why your inlet patch is horizontal and not vertical (second attached image)? Thanks in advance, Paul Last edited by Paul Caicedo; March 23, 2018 at 22:10. |
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#3 |
Super Moderator
Tobias Holzmann
Join Date: Oct 2010
Location: Bad Wörishofen
Posts: 2,712
Blog Entries: 6
Rep Power: 52 ![]() ![]() ![]() |
A) hydraulic diameter
B) yes, it is just a test case without physical condition C) p-rgh is always easy on horizontal patches.
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Keep foaming, Tobias Holzmann |
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#4 |
New Member
Paul
Join Date: Nov 2017
Posts: 15
Rep Power: 9 ![]() |
Hello,
A) Yes, I was trying to calculate with the hydraulic diameter, but for two parallel plates I can't find an equation for Dh. If you have considered the inlet patch as annular diameters, Dh can be easy calculated. B) Is it because g in p-rgh is distributed on the whole area of the patch, but if you consider as vertical it will be distributed only on a line? Thanks, Paul |
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#6 |
Senior Member
Wouter van der Meer
Join Date: May 2009
Location: Elahuizen, Netherlands
Posts: 203
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Hello poulmack,
maybe an addition: two parallel plates have distance d and width w A=w*d U=(w+d)*2 so 4A/U=4w*d/(w+d)/2=2*d because w+d=w, d is small compared to w so dh=2d hope this helps Wouter |
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#7 |
New Member
Paul
Join Date: Nov 2017
Posts: 15
Rep Power: 9 ![]() |
Thanks for your answers.
Regarding radiation, a uniform flux in W/m^2 is set in 0/T using externalWallHeatFluxTemperature in the heaterTop. Then in constant/radiationProperies, there are values of absorptivity and emissivity. Does that it mean that the radiation effect covers the whole model or just only the heaterTop? If it is applied to the whole model, how is possible to create different radiation properties each component of the system (for example to the glass in the cover)? Regards, Paul |
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