TY - CONF

T1 - WAVE TRANSFORMATION at ARTIFICIAL REEFS DESCRIBED by the HILBERT-HUANG TRANSFORMATION (HHT)

AU - Schlurmann, T.

AU - Bleck, M.

AU - Oumeraci, H.

N1 - Cited By :7 Export Date: 1 February 2021

PY - 2003

Y1 - 2003

N2 - Time series of regular and irregular water surface elevations from various experimental configurations are examined with time series analysis methods and Fourier analysis techniques in a laboratory wave flume concerning the hydrodynamic wave damping performance of an artificial reef. The decomposition phenomenon of nonlinear wave trains passing over an artificial reef has been investigated experimentally. It is demonstrated for monocomponent wave trains that the spectral energy distributions and the total amount of energy within the spectra is significantly dependent on the position of a wave gage in the wake of the reef since all Fourier based analysis techniques are incapable to identify nonstationary processes. The Hilbert-Huang Transformation (HHT) is chosen to operate as a more appropriate tool to demonstrate the nonlinear processes of the transmitted transient waves induced by the presence of the artificial reef. Results of this technique are shown and prove that the nonstationary sea states behind the structure are essentially composed of individual dispersive waves which are phase shifted in the wake of the struture and propagating individually to generate a beat effect. Further experiments with irregular waves (JONSWAP) are also carried out and analysed with the HHT. © 2003 World Scientific Publishing Co. Pte. Ltd.

AB - Time series of regular and irregular water surface elevations from various experimental configurations are examined with time series analysis methods and Fourier analysis techniques in a laboratory wave flume concerning the hydrodynamic wave damping performance of an artificial reef. The decomposition phenomenon of nonlinear wave trains passing over an artificial reef has been investigated experimentally. It is demonstrated for monocomponent wave trains that the spectral energy distributions and the total amount of energy within the spectra is significantly dependent on the position of a wave gage in the wake of the reef since all Fourier based analysis techniques are incapable to identify nonstationary processes. The Hilbert-Huang Transformation (HHT) is chosen to operate as a more appropriate tool to demonstrate the nonlinear processes of the transmitted transient waves induced by the presence of the artificial reef. Results of this technique are shown and prove that the nonstationary sea states behind the structure are essentially composed of individual dispersive waves which are phase shifted in the wake of the struture and propagating individually to generate a beat effect. Further experiments with irregular waves (JONSWAP) are also carried out and analysed with the HHT. © 2003 World Scientific Publishing Co. Pte. Ltd.

KW - Coastal engineering

KW - Fisheries

KW - Fourier analysis

KW - Fourier series

KW - Ocean currents

KW - Phase shift

KW - Reefs

KW - Time series analysis

KW - Wakes

KW - Analysis techniques

KW - Hilbert Huang Transformation

KW - Hydrodynamic waves

KW - Laboratory wave flumes

KW - Nonstationary process

KW - Spectral energy distribution

KW - Water surface elevations

KW - Wave transformations

KW - Mathematical transformations

U2 - 10.1142/9789812791306_0151

DO - 10.1142/9789812791306_0151

M3 - Paper

SP - 1791

EP - 1803

ER -