| Autor: |
TANIIKE, Yoshihito, TERAI, Toru, MARUYAMA, Yusuke |
| Jazyk: |
japonština |
| Rok vydání: |
1994 |
| Předmět: |
|
| Zdroj: |
京都大学防災研究所年報. B. 37(B-1):47-55 |
| ISSN: |
0386-412X |
| Popis: |
The streamwise oscillation of rectangular sectioned structures are usually caused by the turbulence of the incident flow but also by the resonance effect due to vortex sheddings from the structure in a low turbulent wind. The unsteady aerodynamic forces on a square-section cylinder which is forced to oscillate harmonically in the along wind direction were measured to investigate the characteristics of the aerodynamic damping and the added mass forces in both smooth and turbulent flows.The streamwise oscillation causes the so-called synchronization in a reduced velocity range around Ur(=U/fmB)=1/2St, where St is the Strouhal number for the stationary cylinder and the corresponding aerodynamic damping becomes negative in the smooth flow.This negative damping effect may cause the vortex resonance with small amplitudes.The added mass coefficient takes a peak value near the synchronization range, which results in the 2 - 3% increase of the actual mass of structures or buildings. The aerodynamic damping approaches a value due to the quasi-steady theory with the increase of the following parameters: turbulence; the amplitude of vibration; and the reduced wind velocity. The mean drag coefficients vary with the amplitudes near and below the the synchronization range, however they reach that of the stationary cylinder in the higher velocity range. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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