New results from the most recent work within the Norwegian Joint Industry Project (JIP) “Higher Order Wave Load Effects on Large Volume Structures” are presented. A nonslender theoretical model is validated from experiments for two fixed, vertical cylinders with different diameter/peak wavelength ratios. A combination of complete diffraction first-order simulations, sum and difference frequency second-order simulations, and third-order FNV (Faltinsen, Newman, and Vinje, nonlinear long wave model) is implemented in order to develop a simplified and robust ringing load model for a large range of cylinder diameter/peak wavelength ratios. Results from the full diffraction second-order analysis show a significant reduction of second-order loads compared to pure FNV in the wavelength range relevant for ringing loads. The results show improved correspondence with high-frequency experimental loads compared with the unmodified FNV. Results for different cylinder peak wavelength ratios are presented, including validation against experiments. In addition, a few simplified response simulations are carried out demonstrating significant improvements with the modified FNV model.

1.
Berhault, C., Coudray, T., and Magne, E., 1992, “Springing and Ringing Effects on Offshore Structures,” 7th International Conference on Floating Production Systems—Blueprints for the 90s.
2.
Eatock Taylor, R., and Hung, S. M., 1987, “Second-order Diffraction Solution on a Vertical Cylinder,” Applied Ocean Research, Vol. 9, No. 1.
3.
Eatock Taylor, R., Rainey, R. C. T., and Dai, D. N., 1992, “Non-linear Hydrodynamic Analysis of TLPs in Extreme Waves: Slender Body and Diffraction Theories Compared,” Proceedings, BOSS, London, U.K.
4.
Falkenberg, E., 1995, SIMO. Program Manual, MARINTEK Report MT51-F93-0184, Sept., Trondheim, Norway.
5.
Faltinsen, O. M., Newman, J. N., and Vinje, T., 1994, “Nonlinear Wave Loads on a Slender Vertical Cylinder,” Journal of Fluid Mechanics, in press.
6.
Huse, E., 1993, “Physics of Ringing Excitation: Preliminary Experiments,” MARINTEK Report 513042.00.01, Trondheim, Norway, Nov.
7.
Krokstad, J. R., and Stansberg, C. T., 1995, “Ringing Load Models Verified Against Experiments,” OMAE, Copenhagen, Denmark.
8.
Malenica
S.
, and
Molin
B.
,
1995
, “
Third-Harmonic Wave Diffraction by a Vertical Cylinder
,”
Journal of Fluid Mechanics
, Vol.
302
, pp.
203
229
.
9.
Marthinsen, T., Stansberg C. T., and Krokstad J. R., 1996, “On the Ringing Excitation of Circular Cylinders,” ISOPE-96, June, Los Angeles, CA.
10.
Newman, J. N., 1994, “Nonlinear Scattering of Long Waves by a Vertical Cylinder,” Symposium in honour of Professor Enok Palm, Oslo, Norway, Nov.
11.
Newman, J. N., 1995, “The Second-Order Wave Force on a Vertical Cylinder,” Preliminary draft, Oct.
12.
Newman, J. N., 1996, “The Second-Order Wave Force on a Vertical Cylinder,” Journal of Fluid Mechanics, Vol. 11.
13.
Stansberg C. T., 1993, “Non-Gaussian Properties of Second–Order Sum Frequency Responses in Irregular Waves: A Numerical Study,” ASME OMAE-Vol. 1, Glasgow, Scotland, pp. 481–489.
14.
Stansberg, C. T., 1995, “Higher Order Wave Loads on a Vertical Column. Model Test Report,” MARINTEK Report 513077.00.01, Trondheim, Norway.
15.
Winterstein, S., 1993, “Ringing Response: Some Statistical Approaches and Areas of Research,” Statoil Report BKON215. Stavanger, Norway, Sept.
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