Wind action at duct bend

[Pawel27]

I am interested in how to apply wind action at duct bend (see green colour in attachment). In case of straight duct line I use "Pressure distribution of circular cylinders" according to EN 1991-1-4 from section 7.9. You can see also this pressure distribution in attachment (section A-A).

I do not know how pressure distribution apply at bend area. Maybe it can be neglected.

 

[JedClampett]

How big of a duct are you talking about here? Is it 24 inches? Or 10 feet. I've seen large ones for air supply and exhaust at power plants.

 

[Pawel27]

It is 78 inches.

 

[JedClampett]

I'd say unless you want to do a wind tunnel analysis to use the same pressure across your entire cross section.

 

[Ron]

The duct will act similar to a smokestack. The bend creates a potentially turbulent condition as wind is shed around the vertical duct and will act like wind blowing along a roof ridge on the horizontal section. They will collide!

Consider an airfoil brace in the bend.