The vibratory response of a long slender riser, made of composite materials and subject to an ocean current, is examined for a range of conditions. A major focus of this study is the performance of composite materials when used for risers. The influence of the number of modes of vibration is studied, as is the influence of the mass ratio and the value of the damping coefficient. The flow past the riser is represented by a shear flow, ranging from Re=8000 at the lower end of the riser to Re=10,000 at the upper end of the riser. The riser vibration is treated as a coupled fluid-flow/vibration problem. The fluid-flow equations are represented by a large eddy simulation model for the wake turbulence present in the flow. Strip theory is used to represent different forcing locations along the length of the riser. Since the composite riser has a material damping that is frequency dependent (it decreases with increasing frequency), its response is different from, say, a steel riser with a constant material damping. The composite riser, with variable damping, has a larger rms displacement than a riser with constant damping, primarily because of the smaller mass ratio. The vibration amplitude is found to increase with an increase in the number of modes.

1.
Yu
,
T. P.
, and
Wang
,
S. S.
, 2004, “
Ultra-Deepwater Composite Risers: Fluid Structure Interactions With Vortex-Induced Vibration
,” Composites Engineering and Applications Center, University of Houston, Report No. CEAC-TR-04-0105.
2.
Al Jamal
,
H.
, and
Dalton
,
C.
, 2004, “
Calculation of Vortex-Induced Vibration at Moderate Reynolds Numbers
,”
J. Fluids Struct.
0889-9746,
19
, pp.
73
92
.
3.
Dong
,
S.
, and
Karniadakis
,
G. E.
, 2005, “
DNS of Flow Past a Stationary and Oscillating Rigid Cylinder at Re=10,000
,”
J. Fluids Struct.
0889-9746,
20
, pp.
519
532
.
4.
Lu
,
X.
,
Dalton
,
C.
, and
Zhang
,
J.
, 1997, “
Application of Large Eddy Simulation Flow Past a Circular Cylinder
,”
ASME J. Offshore Mech. Arct. Eng.
0892-7219,
119
, pp.
219
225
.
5.
Dahlheim
,
J.
, 2000, “
A Numerical Procedure for Prediction of Interference and Collision of Multiple Risers
,”
Proceedings of the ETCE/OMAE/ASME Conference
,
New Orleans
, February.
6.
Evangelinos
,
C.
,
Lucor
,
D.
, and
Karniadakis
,
G. E.
, 2000, “
DNS-Derived Force Distribution on Flexible Cylinders Subject to Vortex-Induced Vibration
,”
J. Fluids Struct.
0889-9746,
14
, pp.
429
440
.
7.
Wang
,
X. Q.
,
So
,
R. M. C.
, and
Liu
,
Y.
, 2001, “
Flow-Induced Vibration of an Euler-Bernoulli Beam
,”
J. Sound Vib.
0022-460X,
243
, pp.
241
268
.
8.
Wang
,
X. Q.
,
So
,
R. M. C.
, and
Chan
,
K. T.
, 2004, “
A Nonlinear Force Model for Vortex-Induced Vibration of an Elastic Cylinder
,”
J. Sound Vib.
0022-460X,
260
, pp.
287
305
.
9.
Schulz
,
K.
, and
Meling
,
T. S.
, 2004, “
Multistrip Numerical Analysis for Flexible Riser Response
,”
Proceedings OMAE/ASME
,
Vancouver, BC, Canada
, June.
10.
Sparks
,
C. P.
, 2001, “
Transverse Modal Vibrations of Vertical Tensioned Risers: A Simplified Approach
,”
Proceedings of OMAE2001
,
Rio de Janeiro
, June, Paper No. OMAE2001/OFT-1201.
11.
Rao
,
S. S.
, 1990,
Mechanical Vibrations
,
2nd ed.
,
Addison-Wesley
,
Reading, MA
.
12.
Wang
,
S. S.
, 2004, private communication.
13.
Kim
,
Y. C.
, and
Triantafyllou
,
M. S.
, 1984, “
The Nonlinear Dynamics of Long Slender Cylinders
,”
ASME J. Energy Resour. Technol.
0195-0738,
106
, pp.
250
256
.
14.
Chopra
,
A. K.
, 2001,
Dynamics of Structures
,
Prentice-Hall
,
Englewood Cliffs, NJ
.
15.
Al Jamal
,
H.
, 2002, “
Two-Dimensional Numerical Study With LES Modeling of Vortex-Induced Vibration of a Circular Cylinder in a Uniform Flow at Moderate Reynolds Number
,” MS thesis, Mechanical Engineering, University of Houston, Houston, TX.
16.
Willden
,
R. H. J.
, and
Graham
,
J. M. R.
, 2004, “
Multi-Modal Vortex-Induced Vibration of a Vertical Riser Pipe Subject to a Uniform Current Profile
,”
Eur. J. Mech. B/Fluids
0997-7546,
23
, pp.
209
218
.
17.
Newman
,
D. J.
, and
Karniadakis
,
G. E.
, 1997, “
A Direct Numerical Simulation of Flow Past a Freely Vibrating Cable
,”
J. Fluid Mech.
0022-1120,
344
, pp.
95
136
.
You do not currently have access to this content.