ANALYSES OF HINGED WAVEMAKERS FOR RANDOM WAVES

Robert T. Hudspeth, Douglas F. Jones, John H. Nath

Abstract


The theoretical dimensionless frequency response functions for the wavemaker stroke spectrum, Qs(iu), and for the wavemaker dynamic pressure moment spectrum, Q^{m), were verified experimentally in the Oregon State University-Wave Research Facility (OSU-WRF) from random waves which were simulated from two types of two-parameter theoretical design wave spectra. The random motions of the wavemaker were first digitally simulated by a unique inverse stacked FFT algorithm which were then used to drive the wavemaker through digital-to-analog converters (DAC). The dimensionless frequency response function for the hydrodynamic pressure moment spectrum was not measured directly but was computed from the dynamic covariance equations for a hinged wavemaker of variable-draft by linear combinations of related dimensionless frequency response functions and cross-spectral estimates. The measured estimates were found to agree reasonably well with the analytical approximations, and these measured stochastic hydrodynamic pressure moment estimates on a hinged wavemaker of variable draft are believed to be unique.

Keywords


hinged wavemaker; random waves; wave analysis

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