The dynamics of regular breaking waves has been both widely and successfully investigated. In any case, many natural coastal processes are commonly due to irregular breaking waves, the behaviour of which requires thorough study. The present research aims to investigate the distributions of the wave and turbulent Reynolds shear stresses in a laboratory irregular wave, characterized by a narrow banded spectrum, which develops on a sloping sand bottom, in intermediate waters. Experiments focused on the wave shoaling region, in order to analyze the effects of breaking induced turbulence outside the surf zone, taking into account that turbulence is not limited to the breaking region but it spreads also outside the surf zone. The phase-averaging technique was used to separate the turbulent components from the steady ones. All the analysed values derive directly from real measurements and are not interpolated. Moreover, a 3D Acoustic Doppler Velocimeter was adopted to measure the wave velocity, consequently the longshore component of the velocity is also available to estimate the shear stresses. These experimental data were also used to test some literary numerical models and relevant results have been obtained, which confirm the outputs of the abovementioned models in the cases of non dissipative waves propagating above a flat bottom and dissipative waves propagating over a sloping bottom.

Wave and turbulent Reynolds stresses in irregular shoaling waves

Ben Meftah M;De Serio F;Mossa M;Petrillo AF
2012

Abstract

The dynamics of regular breaking waves has been both widely and successfully investigated. In any case, many natural coastal processes are commonly due to irregular breaking waves, the behaviour of which requires thorough study. The present research aims to investigate the distributions of the wave and turbulent Reynolds shear stresses in a laboratory irregular wave, characterized by a narrow banded spectrum, which develops on a sloping sand bottom, in intermediate waters. Experiments focused on the wave shoaling region, in order to analyze the effects of breaking induced turbulence outside the surf zone, taking into account that turbulence is not limited to the breaking region but it spreads also outside the surf zone. The phase-averaging technique was used to separate the turbulent components from the steady ones. All the analysed values derive directly from real measurements and are not interpolated. Moreover, a 3D Acoustic Doppler Velocimeter was adopted to measure the wave velocity, consequently the longshore component of the velocity is also available to estimate the shear stresses. These experimental data were also used to test some literary numerical models and relevant results have been obtained, which confirm the outputs of the abovementioned models in the cases of non dissipative waves propagating above a flat bottom and dissipative waves propagating over a sloping bottom.
XXXIII convegno nazionale di idraulica e costruzioni idrauliche : Brescia, 10-14 settembre 2012
978-88-97181-18-7
EdiBios
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11589/13263
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