asce wind loads session 1-2 wind engineering theory: bluff body aerodynamics
TRANSCRIPT
ASCE Wind Loads
SESSION 1-2Wind Engineering Theory:Bluff Body Aerodynamics
ASCE Wind Loads
Introduction
Buffeting - Forced vibration from upwind turbulent winds (Note - I say vibrations for a stiff or flexible structure)
Vortex Induced Motion - Forced vibration from regular turbulence in wake (downwind)
Aeroelastic Vibrations - Vibrations caused by motion dependent aerodynamic loads
ASCE Wind Loads
Bernoulli's Equation
Along a streamline
21Constant
2p U h
2
- static pressure
1 - dynamic pressure
2 - pressure due to elevation
(typically negligible in wind
loading cases)
p
U
h
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BERNOULLI'S EQUATION
NB ~ UNLESS NOTED, ALL PRESSURES ARE SUCTIONS (NEG)ALL PRESSURES ARE DYNAMIC, i.e., p(t)
ASCE Wind Loads
PRESSURE COEFFICIENTS
21
2 pp t u C
NB ~ PRESSURES ARE A FUNCTION OF THE BUILDING SHAPE AND THE WIND SPEED.PRESSURE COEFFICIENTS ARE A FUNCTION OF THE SHAPE ALONE.
ASCE Wind Loads
PRESSURE COEFFICIENTS
pSMOOTH LAMINAR FLOW (C ' FROM THEORY)s
pTURBULENT SEPARATED FLOW (C ' FROM EXPERIMENT)s
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Video of Cladding Pressures Courtesy of Wind Science and Engineering, Texas Tech Univ.
ASCE Wind Loads
Cladding PressuresCourtesy of Wind Science and Engineering, Texas Tech Univ.
ASCE Wind Loads
Cladding PressuresCourtesy of Joe Minor, Consulting Engineer
ASCE Wind Loads
Cladding PressuresCourtesy of Wind Science and Engineering, Texas Tech Univ.
ASCE Wind Loads
Cladding PressuresCourtesy of Wind Science and Engineering, Texas Tech Univ.
ASCE Wind Loads
Cladding PressuresCourtesy of Wind Science and Engineering, Texas Tech Univ.
ASCE Wind Loads
Cladding PressuresCourtesy of Wind Science and Engineering, Texas Tech Univ.
ASCE Wind Loads
Cladding PressuresCourtesy of Wind Science and Engineering, Texas Tech Univ.
ASCE Wind Loads
Cladding PressuresCourtesy of Wind Science and Engineering, Texas Tech Univ.
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Internal PressuresCourtesy of Joe Minor, Consulting Engineer
ASCE Wind Loads
Internal PressuresCourtesy of Joe Minor, Consulting Engineer
ASCE Wind Loads
Internal Pressures Courtesy of Wind Science and Engineering, Texas Tech Univ.
ASCE Wind Loads
Internal PressuresCourtesy of Wind Science and Engineering, Texas Tech Univ.
ASCE Wind Loads
Internal PressuresCourtesy of Wind Science and Engineering, Texas Tech Univ.
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Vortex Shedding
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Wind tunnel: Vortex shedding
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Aeroelastic Action
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Aeroelastic BehaviorTacoma Narrows Bridge