GALLOPING OSCILLATIONS OF PRISMATIC STRUCTURES
GALLOPING OSCILLATIONS CAN ARISE ABOVE A CERTAIN WIND VELOCITY WITH LATERAL FORCE COEFFICIENT A SUB ONE GREATER THAN O (UNSTABLE CROSS SECTIONS) AND ALSO AT A SUB ONE LESS THAN OR EQUAL TO O (TABLE CROSS SECTINS). IN THE LATTER CASE, AN INITIAL DISTURBANCE IS ALSO NECESSARY TO TRIGGER THE VIBRATIONS. THIS TRIGGERING DISTURBANCE MUST BE LARGER THAN THE UNSTABLE AMPLITUDE, PROPORTIONAL TO STRUCTURAL DAMPING, AND IN SOME CASES MUST BE ABLE TO DECREASE WITH INCREASING WIND VELOCITY. THE ONSET VELOCITIES ARE HIGHER WITH A SUB-ONE LESS THAN OR EQUAL TO O AND ARE DIRECTLY PROPORTIONAL TO STRUCTURAL DAMPING, IN ALL CASES. TURBULENCE CAN DRASTICALLY CHANGE THE AEROELASTIC STABILITY OF PRISMATIC BODIES. WITH RECTANGULAR CROSS SECTIONS OF 2/1 THE TENDENCY TO GALLOPING INSTABILITY FROM ZERO POSITION DECREASES WITH INCREASING TURBULENCE INTENSITY AND CAN VANISH AT INTENSITIES OF 8% OR SO. ON THE CONTRARY, PRISMS OF 1/2, STABLE IN THE SMOOTH FLOW, CAN BECOME UNSTABLE IN THE TURBULENT FLOW AND THEIR TENDENCY TO GALLOPING OSCILLATIONS INCREASES WITH TUBULENCE INTENSITY. /ASCE/
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Availability:
- Find a library where document is available. Order URL: http://worldcat.org/issn/07339399
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Supplemental Notes:
- Vol 98, No EM1, PROC PAPER 8692, PP 27-46, 11 FIG, 1 TAB,
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Authors:
- Novak, M
- Publication Date: 1972-2
Media Info
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Serial:
- Journal of Engineering Mechanics
- Publisher: American Society of Civil Engineers
- ISSN: 0733-9399
- EISSN: 1943-7889
- Serial URL: http://ascelibrary.org/journal/jenmdt
Subject/Index Terms
- TRT Terms: Aerodynamics; Flow; Fluid dynamics; Oscillation; Prisms; Turbulence; Velocity; Wind
- Candidate Terms: Turbulent flow
- Uncontrolled Terms: Fluid flow
- Old TRIS Terms: Wind velocity
- Subject Areas: Bridges and other structures; Highways;
Filing Info
- Accession Number: 00209616
- Record Type: Publication
- Files: TRIS
- Created Date: Apr 10 1972 12:00AM