BLDG365 #10-Wind-Handout.pdf - BLDG365 Building Science...

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BLDG365 Building Science 2021-04-04 Chang-Seo Lee 1 BLDG 365 Building Science Wind and Buildings Winter 2021 Chang-Seo Lee, Ph.D. Dept. of Building, Civil & Environmental Engineering Concordia University 1 Wind Effects on Building Design Structural integrity and safety Heat transfer and energy consumption Pollution transport and ventilation Driving rain and deposition of snow Comfort and safety of pedestrian 4/4/2021 2 1 2
BLDG365 Building Science 2021-04-04 Chang-Seo Lee 2 Basic Definitions Average wind speed (V), Standard deviation( v ), Gust (G) 4/4/2021 3 Basic Definitions Average wind speed (V): Variance (σ v 2 ), Standard deviation (σ v ) Turbulent intensity or relative gustiness (I V ) 4/4/2021 4 ) ( ) ( 1 2 2 2 2 1 t t dt V V t t t V ) ( 1 2 2 1 t t dt V V t t t V I V V 3 4
BLDG365 Building Science 2021-04-04 Chang-Seo Lee 3 Wind Speed Effects 5 Baniotopoulos, C. et al. (2011)Environmental Wind Engineering and Design of Wind Energy Structures, SpringerWienNewYork Wind and Height Gradient height (Zg) Height that the surface roughness has no effect on wind Zg is a function of terrain Wind speed (V), and gust (G) at elevation Z 4/4/2021 6 g g g g z g g z V G Z Z G G Z Z V V 35 . 1 5 6
BLDG365 Building Science 2021-04-04 Example Problem: If the wind speed in an open airport at 10 m height is 40 m/s, what is the wind speed at the same height in a suburban area?
Chang-Seo Lee 4 4/4/2021 7 Wind Effects on Stationary Objects Direct positive pressure Aerodynamic drag Negative pressure Rocking effect Harmonic effect (vibration) Clean-off effect 8 7 8
BLDG365 Building Science 2021-04-04 Chang-Seo Lee 5 Wind Flow around Buildings 4/4/2021 9 Wind Pressure on Buildings Wind velocity pressure (dynamic pressure): 𝑃 = ఘ௏ V H : approaching wind speed at building height [m/s] : ambient air density [kg/m 3 ] Building surface pressure relative to barometric pressure 𝑃 = 𝐶 𝑃 C p : Wind pressure coefficient [dimensionless] Max. pressure be at gust 𝑃 ௠௔௫ = 𝐶 𝑃 = 𝐶 𝜌𝐺 2 10 9 10

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