TY - GEN
T1 - A small scale experiment for multi-modal VIV response of a long flexible horizontal cylinder
AU - Prastianto, Rudi Walujo
AU - Otsuka, Koji
AU - Ikeda, Yoshiho
PY - 2007
Y1 - 2007
N2 - Vibration response of a long flexible horizontal cylinder having pretension in water flow is very complex. Some phenomena which were still not clearly understood have been found in its motion behavior. This paper presents experimental results of a long flexible horizontal cylinder have been towed in still water which is free to respond in both, in-line and transverse directions. The length-to-diameter ratio of the test model was around 269 with a mass ratio of 1.7. Reynolds number varied from 9 × 102 up to 4.5 × 103. The model was positioned in two angles of 0 and 5 degree in horizontal plane which respect to the fluid flow. Pretension was applied to the test cylinder for towing speed of 0.1 up to 0.5 m/s in each case of the test. The motion data were recorded as digital image data using some CCD cameras and were analyzed using image processing technique. The frequencies of the CF (cross-flow) VIV response follow the Strouhal frequencies for a constant Strouhal number (St = 0.166) for both cylinder position, θ = 0 and θ = 5 degree respectively. It was found that multi-mode responses occurred at higher flow velocities. Further analysis will be done and additional results will be published later.
AB - Vibration response of a long flexible horizontal cylinder having pretension in water flow is very complex. Some phenomena which were still not clearly understood have been found in its motion behavior. This paper presents experimental results of a long flexible horizontal cylinder have been towed in still water which is free to respond in both, in-line and transverse directions. The length-to-diameter ratio of the test model was around 269 with a mass ratio of 1.7. Reynolds number varied from 9 × 102 up to 4.5 × 103. The model was positioned in two angles of 0 and 5 degree in horizontal plane which respect to the fluid flow. Pretension was applied to the test cylinder for towing speed of 0.1 up to 0.5 m/s in each case of the test. The motion data were recorded as digital image data using some CCD cameras and were analyzed using image processing technique. The frequencies of the CF (cross-flow) VIV response follow the Strouhal frequencies for a constant Strouhal number (St = 0.166) for both cylinder position, θ = 0 and θ = 5 degree respectively. It was found that multi-mode responses occurred at higher flow velocities. Further analysis will be done and additional results will be published later.
KW - Image processing technique
KW - In-line and cross-flow motion
KW - Long flexible cylinder
KW - Multi-modal vortex-induced vibration (VIV) response
UR - http://www.scopus.com/inward/record.url?scp=36448974502&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:36448974502
SN - 1880653680
SN - 9781880653685
T3 - Proceedings of the International Offshore and Polar Engineering Conference
SP - 2758
EP - 2763
BT - Proceedings of The Seventeenth 2007 International Offshore and Polar Engineering Conference, ISOPE 2007
T2 - 17th 2007 International Offshore and Polar Engineering Conference, ISOPE 2007
Y2 - 1 July 2007 through 6 July 2007
ER -