Experimental investigation of non-linear irregular wave kinematics
- Danish Hydraulic Inst., Hoersholm (Denmark)
- Norwegian Maritime Academy, Trondheim (Norway)
- Ramboell, Esbjerg (Denmark)
A number of different long-crested seastates were generated and the surface elevation time series and the associated wave particle velocity profiles were measured. The wave surface elevations were measured by conductance type wave gauges. The water particle velocities were measured by ultrasonic velocity meters installed at fixed positions and in a rig following the wave surface. All three components of wave particle velocities were measured at four fixed elevations below the still water surface, and at four dynamic elevations below the moving wave surface. Water particle accelerations were determined by means of numerical differentiation of the particle velocities. The measured wave kinematics have been compared with wave kinematics predicted by Wheeler stretching of the measured wave elevation time series. It was found that Wheeler stretching predicts the kinematics of not too steep waves with reasonable accuracy. For the irregular seastates containing very steep waves a new procedure has been proposed. This new procedure has been based on Pierson`s third order perturbation solution for sums of long-crested Stokes waves in deep water. The procedure assumes that the peak of the wave spectrum may be modelled by a small number of interacting Stokes waves and that the kinematics from the remaining part of the spectrum may be modelled by a stretching approach. The present paper shows some preliminary results where the peak of the wave spectrum has been modelled by two interacting Stokes waves and the remaining part of the spectrum has been modelled by linear wave theory using the wave superposition method by Donelan et al (1992) to describe the wave kinematics. Very good correlations have been found between the kinematics measured in a very steep transient wave generated according to the New Wave principle and the kinematics predicted by the new approach.
- OSTI ID:
- 449651
- Report Number(s):
- CONF-9606279-; ISBN 0-7918-1490-4; TRN: IM9714%%208
- Resource Relation:
- Conference: 14. international conference on offshore mechanics arctic engineering (OMAE), Florence (Italy), 16-20 Jun 1996; Other Information: PBD: 1996; Related Information: Is Part Of Proceedings of the 15. international conference on offshore mechanics and arctic engineering -- OMAE 1996. Volume 1, Part A: Offshore technology; Chakrabarti, S.K. [ed.] [Chicago Bridge and Iron Technical Services Co., Plainfield, IL (United States)]; Pontes, M.T. [ed.] [Inst. Nacional de Engenharia e Tecnologia Industrial, Lisbon (Portugal)]; Maeda, Hisaaki [ed.] [Univ. of Tokyo (Japan)]; Falzarano, J. [ed.] [Univ. of New Orleans, LA (United States)]; Schofield, P. [ed.] [W.S. Atkins, Surrey (United Kingdom)]; Morrison, D. [ed.] [Shell E and P Technology Co., Houston, TX (United States)]; PB: 530 p.
- Country of Publication:
- United States
- Language:
- English
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