Wind Speed and RILEM Tubes

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Anonymous Poster	Wind Speed and RILEM Tubes 07/20/2010 12:07 PM
	Does anyone know how the RILEM tube windspeeds are calculated? There is the equation Q (kg/m2) = Velocity*2/16 but I'm not sure how this is derived.
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PMoon Power-User Join Date: Feb 2010 Location: Florida Posts: 259 Good Answers: 29	#1 Re: Wind Speed and RILEM Tubes 07/20/2010 4:47 PM
	Excerpt from: WaterSealant.com The height of the column of water, as measured from the center of the bowl to the meniscus in the tube, determines the hydrostatic pressure applied to the test area. This pressure can subsequently be converted into a velocity, or wind-driven rain speed. As an example, if the tube is filled to the "0.0 mL" graduation, this exerts a pressure of 1139.36 Pa, which correlates to a 98.1-mph wind-driven rain. Filling the tube to the "2.5 mL" graduation correlates to a 78.2-mph wind-driven rain. __________________ Si vis pacem, para bellum
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eric rirsch Participant Join Date: Jul 2010 Posts: 3	#3 In reply to #1 Re: Wind Speed and RILEM Tubes 07/21/2010 4:23 AM
	Thanks "PMoon" That's very helpful. It looks like a simple calculation to calculate the pressure from the weight of water (i.e. massgravityheight) I was wondering how I could get to the relationship between this pressure and the velocity. Any ideas? Eric _____ "Make tea not war"
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ba/ael Guru Join Date: Nov 2007 Location: Sherwood Park, Alberta, Canada Posts: 1212 Good Answers: 74	#4 In reply to #3 Re: Wind Speed and RILEM Tubes 07/25/2010 7:11 PM
	From Appendix C of the National Building Code of Canada, pressure and wind velocity are related by the formula: q = ρV²/2 where q is the pressure in Pascals, ρ is the density of dry air at 0^oC, taken in Canada as 1.2929 kg/m3 and V is wind velocity in m/s. If you want it in Imperial units, you will need to do the appropriate conversions. __________________ Bruce
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eric rirsch Participant Join Date: Jul 2010 Posts: 3	#5 In reply to #4 Re: Wind Speed and RILEM Tubes 07/26/2010 4:35 AM
	Thanks a lot Bruce, that's spot on. Eric
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