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Re: [EnergyPlus_Support] Airflow_Network_Geometry



Interesting...thanks.

asce7-2002 p72

Wind forces shall be applied in the directions resulting in maximum member forces
and reactions. For towers with square cross-sections, wind forces shall be
multiplied by the following factor when the wind is directed along a tower
diagonal:

1 + 0.75 E, but not > 1.2

E : ratio of solid area to gross area of one tower face for the segment under
consideration.

2014-09-09 18:30 GMT+02:00 'Edward G. Lyon' eglyon@xxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx>:
 

ASCE 7 has structural wind coefficient data for other shapes. You can probably get some better values there. 

Sent from my iPhone

On Sep 9, 2014, at 10:36 AM, "michele.rossi@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

 

I have already thought the algorithm that Airflow Network uses to calculate this was based on rectangular buildings with flat roofs. But, I want to check it. 

I totally agree with you, CFD is the best tool to find the WPCs accurately for all geometries types. But, I will search another simple ones ou some databases to adjust these WPCs and consequently improve the simulation results.

Thank you very much for your help! 

---In EnergyPlus_Support@xxxxxxxxxxxxxxx, <jeannieboef@...> wrote :

You can use it on a banana shaped building...the algorithm is based on corrilations from rectangular buildings with flat roofs and within certain aspect ratio limits, but it can be applied to anything, only that the accuracy is likely to diminish more the further away you are from the corrilation data set.

Use it and then adjust those surfaces where it would not apply well manually, such as inner courtyards.

Else, google some other tools that you can use to find the WPCs...CFD is the best and can handle all geometries accurately.

Mit freundlichen Grü�en- Sent from my iPhone (excuse the brevity)

i. A.
Jean Marais
b.i.g. bechtold

On 05.09.2014, at 18:41, "michele.rossi@... [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

 

Hello everyone,


I have a doubt about the Wind pressure coefficients (WPC) in the
Airflow Network group in EnergyPlus (natural ventilation modeling).

Can I use the option Surface Average Calculation for the WPCs if the
building has a rectangular plan with pitched roof (see the attached file)?

The I/O Reference Manual does not explain anything about the roof. It
only mentions that the building must be rectangular.


Thank you very much,


Michele Rossi.


<geometry.png>
 




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Posted by: Jean Marais <jeannieboef@xxxxxxxxx>


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