@phdthesis{oai:ynu.repo.nii.ac.jp:00007693,
 author = {Vo, Duy Hung},
 month = {Sep},
 note = {In the past, during construction or once the bridge was completed and in service stage, stay cable had known to vibrate due to rain-wind combination, which named rain-wind induced vibration (RWIV). Recently, it was also proved that stayed-cables could be excited even though in no rain condition that called dry galloping (DG). For RWIV, rain plays an important role in forming the lower and upper rivulets on cable surface that change the cable aerodynamic characteristics, and then excite galloping. This phenomenon can be mitigated by shape modification or increasing the Scruton number of cable. Together with that, dry galloping is classified as one of the wind-induced large amplitude vibration phenomena in dry weather (without rain), usually occurs at relatively high-reduced wind speed, it also showed some characteristics of limited amplitude vibration, however. Some studies showed the existence of dry galloping, in both wind tunnel test and the site observation. Nevertheless, its characteristics and mechanism are not fully understood as well as control methods for this phenomenon are under developing. Recently, some authors pointed out that current aerodynamic mitigation methods can adapted for RWIVs but not for the DG. The present research is therefore an effort to investigate insight of DG characteristics and its mechanism as well as develop an effective countermeasure for DG and RWIV. Experimental and analytical results proved that DG depends on wind attack angles and it is less sensitive to the cable damping change rather than frequency and it can occur in subcritical Re region. Moreover, there is a strong recovery of surface pressure in leeward side and in presence of single spiral protuberances, cable surface pressure redistributed. The mechanism of DG relate to the interruption of Karman vortex shedding and the excitation from low frequency flow/vortices at high wind speed. Further, its interaction with axial flow, wind attack angle are significant in forming dry galloping conditions. In addition, to assess the efficiency of current control methods for suppression the DG and RWIV, parallel protuberances and pattern-indented surface cables are investigated in low Scruton number range to reconfirm the efficiency. The results reaffirmed that DG only occurred in specific condition of wind-cable angle, wind speeds. Further, the cable with indented surface and parallel protuberances still exhibited large amplitude vibration in low Scruton number. Due to the fact like that, this study will continue developing an aerodynamically cable for suppressing wind and rain-wind induced vibration, named spiral protuberances. The recommendation for fabrication of spiral protuberance cable will be issued in considering the selective fillet sizes and fillet pitches and number of protuberances. Finally, the suppression mechanism of spiral protuberance cable and its stability characteristic will be discussed in detail.},
 school = {横浜国立大学},
 title = {Characteristics of stay cable dry galloping and effectiveness of spiral protuberance countermeasures},
 year = {2016}
}