TY - GEN

T1 - Wave forces on horizontal cylinders at low keulegan-carpenter and reynolds numbers

AU - Koterayama, Wataru

AU - Hu, Changhong

PY - 1995

Y1 - 1995

N2 - Hydrodynamic forces on a horizontal cylinder with circular and elongated rectangular cross-section in regular waves are studied experimentally and numerically. In the laboratory experiment, the cylinder is fixed beneath waves with its axis parallel to the wave crests. The kinematics of the wave flow are determined from linear wave using measured wave height and period, and the experiment is conducted at low Kc and relatively low Re values (Kc < 6 and 10,000 < Re < 30,000). In addition, we present a numerical simulation method for a two dimensional flow around a cylinder undergoing orbital motion in still water. Results on the horizontal cylinder show that the trend of both drag and inertia coefficients is quite different from those obtained from planar oscillatory flow test (or a vertical cylinder). From the numerical simulation it is found that vortex shedding begins at about Kc = 1.5 for a circular cylinder in orbital motion, much smaller than that in planar oscillation. For the elongated rectangular cylinder, the force coefficients are much more complicated than the circular cylinder because the flow always separates. It is found that the forces on a elongated rectangular cylinder fixed in waves are generally much larger than that harmonically oscillating in still water at the same Kc and Re numbers.

AB - Hydrodynamic forces on a horizontal cylinder with circular and elongated rectangular cross-section in regular waves are studied experimentally and numerically. In the laboratory experiment, the cylinder is fixed beneath waves with its axis parallel to the wave crests. The kinematics of the wave flow are determined from linear wave using measured wave height and period, and the experiment is conducted at low Kc and relatively low Re values (Kc < 6 and 10,000 < Re < 30,000). In addition, we present a numerical simulation method for a two dimensional flow around a cylinder undergoing orbital motion in still water. Results on the horizontal cylinder show that the trend of both drag and inertia coefficients is quite different from those obtained from planar oscillatory flow test (or a vertical cylinder). From the numerical simulation it is found that vortex shedding begins at about Kc = 1.5 for a circular cylinder in orbital motion, much smaller than that in planar oscillation. For the elongated rectangular cylinder, the force coefficients are much more complicated than the circular cylinder because the flow always separates. It is found that the forces on a elongated rectangular cylinder fixed in waves are generally much larger than that harmonically oscillating in still water at the same Kc and Re numbers.

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M3 - Conference contribution

AN - SCOPUS:0010303184

SN - 1880653168

T3 - Proceedings of the International Offshore and Polar Engineering Conference

SP - 189

EP - 195

BT - 5th International Offshore and Polar Engineering Conference, ISOPE 1995

PB - International Society of Offshore and Polar Engineers

T2 - 5th International Offshore and Polar Engineering Conference, ISOPE 1995

Y2 - 11 June 1995 through 16 June 1995

ER -