선수각 변화가 굽은 라이저 국부압력 및 하중계수에 미치는 특성에 관한 실험연구

Abstract

The present study is aimed to experimentally identify the effect of the incident flow angle on the local pressure and force coefficients of the curved riser. Unlike previous studies mainly focused on the low Reynolds number below 104, the higher Reynolds numbers up to are considered in the present study. This approach can be contributed to understanding more realistic force feature of the curved riser. To measure the local pressures on riser’s surface, according to the incident flow angle, the wind tunnel test was conducted in KOCED Wind Tunnel Facility with PSI8400 system, where the incident flow angles, , were considered in the range of . Moreover, the pressure tabs are placed in the local sections of the riser, and thereby the positions are defined by the inclination angle of the curved axis. Based on the measured local pressures in the circumferential direction of riser’s surface, the load coefficients were also estimated. The results show that there are substantial variations of the sectional force coefficients, according to the incident flow angle, and the force variations are dominant to its angle rather than the Reynolds number. From this experiment, the contour map of the load distribution, regarding the incident angle, was established and can be considered as the force database. The experimental results are physically reasonable and give us a physical insight into the relationship between the variations