REDUCTION COEFFICIENT FOR WIND LOADING

[eriksasha]

Hi,

I'm looking at how to determine a reduction factor for a wind load acting on a cylindrical form(diam. 550mm). The 50m/s wind load exerts a pressure of 1.5kN/m2 on the form.

To determine a line load vertically on the form I simply multiply the pressure by the diam. which gives me a line load vertically on the form of 0.825kN/m.

I'm thinking that I must be able to reduce this value by some factor taking into account the cylindrical form.

I'm at a loss to find this information. The determining of reynolds number, I am aware of but how to then determine a factor for if I get turbulent or smooth air flow I am not aware of.

Any assistance is greatly appreciated.

All the best

Joey

 

[patswfc]

Are you working in the UK?

If so BS6399-2 gives a force coefficient of 1.2 for circular elements. It seems very crude as it doesnt seem to
account for the flow regime (sub or super critical flow).

There is a BRE publiction (

http://www.bre.co.uk)

Special Digest 5 "Wind loads on unclad frames" which goes into more detail to calculate a force coefficient for circular elements based on the flow regime.

 

[eriksasha]

Thanks for the reply!

all the best