Growth and dissipation of wind forced, deep water waves

Laurent Grare (1) , William L. Peirson (2) , Hubert Branger (1) , J. Walker (2) , Jean-Paul Giovanangeli (1) , Vladimir K. Makin (3)

1 IRPHE - Institut de Recherche sur les Phénomènes Hors Equilibre
2 WRL - Water Research Laboratory
3 Observation and Modelling Department

The input of energy by wind to water waves is compared with the observed growth of the waves using a suite of microphysical measurement techniques in the laboratory. These include measured tangential stresses in the water and air immediately adjacent to the interface with corresponding form drag measurements above wind-forced freely-propagating waves. The drag data sets are consistent but the comparison has highlighted important issues in relation to the measurement of fluctuating pressures above freely-propagating waves. Derived normalised wind input values show good collapse as a function of mean wave steepness and are significantly in excess of the assembly of net wave growth measurements by Peirson and Garcia (2008) at low steepness. Sheltering coefficients in the form of Jeffreys (1925) are derived that are consistent with values previously obtained by Donelan (1987; 1999; 2006). The sheltering coefficients exhibit substantial scatter. By carefully measuring the associated growth of the surface wave fields, systematic energy budgets for the interaction between wind and waves are obtained. For non-breaking waves, there is a significant and systematic misclose in the radiative transfer equation if wave-turbulence interactions are not included. Significantly higher levels of turbulent wave attenuation are found in comparison with the theoretical estimates by Teixeira and Belcher (2002) and Ardhuin and Jenkins (2005). Suitable normalisations of attenuation for wind-forced wave fields exhibit consistent behaviour in the presence and absence of wave breaking. Closure of the surface energy flux budget is obtained by comparing the normalised energy loss rates due to breaking with the values previously determined by Banner and Peirson (2007) and Drazen et al. (2008) when expressed as a function of mean wave steepness. Their normalised energy loss rates obtained for non-wind forced breaking wave groups are remarkably consistent with the levels found during this present study when breaking waves are subject to wind forcing.

Mots clés: wind waves; wave tank experiment; wave growth; static pressur; form drag; viscous drag

Domaines: Mécanique des fluides [physics.class-ph]; Mécanique des fluides [physics.class-ph]; Océan, Atmosphère

Laurent Grare, William L. Peirson, Hubert Branger, J. Walker, Jean-Paul Giovanangeli, et al.. Growth and dissipation of wind forced, deep water waves. Journal of Fluid Mechanics, 2013, 722, pp.5-50. ⟨10.1017/jfm.2013.88⟩. ⟨hal-00850963⟩