Ripples damping due to monomolecular films

Cini, Renzo; Lombardini, P. P.; Manfredi, Claudia; Cini, Enrico

doi:10.1016/0021-9797(87)90246-3

Cited by 34 publications

(12 citation statements)

References 14 publications

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“…However, we can make further deductions regarding surfactant influences on gas transfer by examining the high wave number region of the slope spectrum. Theoretical formulations of wave damping in the presence of viscoelastic films predict that the introduction of a small finite viscoelastic modulus impacts the high wave number region of the slope spectrum most strongly [ Lucassen‐Reynders and Lucassen , 1969; Lucassen‐Reynders , 1986; Cini et al , 1987; Bock and Mann , 1989]. As viscoelasticity increases, the damping phenomenon affects waves of increasingly lower wave number.…”

Section: Resultsmentioning

confidence: 99%

Air‐sea gas transfer: Its dependence on wind stress, small‐scale roughness, and surface films

et al. 2004

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[1] The influence of wind stress, small-scale waves, and surface films on air-sea gas exchange at low to moderate wind speeds (<10 m s À1 ) is examined. Coincident observations of wind stress, heat transfer velocity, surface wave slope, and surface film enrichments were made in coastal and offshore waters south of Cape Cod, New England, in July 1997 as part of the NSF-CoOP Coastal Air-Sea Chemical Fluxes study. Gas transfer velocities have been extrapolated from aqueous heat transfer velocities derived from infrared imagery and direct covariance and bulk heat flux estimates. Gas transfer velocity is found to follow a quadratic relationship with wind speed, which accounts for $75-77% of the variance but which overpredicts transfer velocity in the presence of surface films. The dependence on wind stress as represented by the friction velocity is also nonlinear, reflecting a wave field-dependent transition between limiting transport regimes. In contrast, the dependence on mean square slope computed for the wave number range of 40-800 rad m À1 is found to be linear and in agreement with results from previous laboratory wind wave studies. The slope spectrum of the small-scale waves and the gas transfer velocity are attenuated in the presence of surface films. Observations over largescale gradients of biological productivity and dissolved organic matter show that the reduction in slope and transfer velocity are more clearly correlated with surface film enrichments than with bulk organic matter concentrations. The mean square slope parameterization explains $89-95% of the observed variance in the data and does not overpredict transfer velocities where films are present. While the specific relationships between gas transfer velocity and wind speed or mean square slope vary slightly with the choice of Schmidt number exponent used to scale the heat transfer velocities to gas transfer velocities, the correlation of heat or gas transfer velocity with mean square slope is consistently better than with wind speed.

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Section: Resultsmentioning

confidence: 99%

Air‐sea gas transfer: Its dependence on wind stress, small‐scale roughness, and surface films

et al. 2004

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“…The interaction of soluble and insoluble surfactants with water waves has intrigued scientists for many centuries (Franklin 1774;Giles 1969) and remains the focus of current research efforts involving synthetic aperture radar imaging of the ocean (Jahne and Riemer 1990;Ochadlick et al 1992;Onstott and Rufenach 1992;Peltzer et al 1992). Although many previous studies have involved waves and surfactants on air±water interfaces (Scriven 1960;Levich 1962;Mann and Hansen 1963;Lucassen and Hansen 1967;Miles 1967;LucassenReynders and Lucassen 1969;Hansen and Ahmad 1971;Hedge and Slattery 1971;Edwards et al 1991;Cini and Lombardini 1981;Cini et al 1987;Bock 1987;Bock and Mann 1989;Bock 1989a, b;Bock 1991;Bock and Frew 1993), relatively few experimental investigations have involved soluble surfactants (Cini and Lombardini 1981;Cini et al 1987;Bock 1987;Bock and Frew 1993) even though soluble surfactants are a common constituent of the marine microlayer (Zutic et al 1981;Bock and Frew 1993). Essentially all experimental soluble surfactant studies have emphasized the wave damping properties of the surfactants, thereby leaving the effects of surfactants on wave propagation speed unreported.…”

Section: Introductionmentioning

confidence: 99%

Linear and nonlinear gravity-capillary water waves with a soluble surfactant

Lapham

Dowling²,

Schultz³

2001

Experiments in Fluids

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Naturally occurring soluble-surfactant slicks in¯uence the properties of water waves. This paper describes results from wave tank experiments involving a soluble surfactant, and linear and nonlinear gravitycapillary waves. Instantaneous surface de¯ections were measured using optical techniques to determine the damping, phase speed, and the frequency content of the waves for wavemaker frequencies from 4 to 22 Hz. Measured linear-wave phase speed and damping agree well with existing theory at surfactant concentrations away from that leading to maximum damping. Under conditions leading to nonlinear waves, an as-yet-unexplained subharmonic wave with one-sixth the wavemaker frequency was found only with soluble surfactant present.

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“…In the past, the effect of viscoelastic films on the damping of small-wavelength capillary waves has been investigated mainly by chemists, who used this effect to study the rheological properties of surface-active materials (for a review, see Lucassen-Reynders [1985]). Only in the last few years has it been realized that such films can give rise to a resonance-type or anomalous damping in the shortgravity-wave region [Cini and Lombardini, 1978;Lucassen, 1982;Hiihnerfuss, 1986;Cini et al, 1987].…”

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confidence: 99%

“…In section 2 we briefly sketch the basic underlying physics of the Marangoni wave theory. For details, the reader is referred to the book of Levich [1962] and to the papers by Lucassen-Reynders and Lucassen [1969], Cini and Lombardini [1978], and Cini et al [1987] or to the appendix of this paper. The appendix has been added because in Levich's [1962] book, equations (121-18) and (121-19) contain a sign error (apparently a misprint) which is perpetuated throughout the literature and which has resulted in incorrect formulae for the damping coefficient appearing in many papers.…”

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confidence: 99%

The damping of ocean waves by surface films: A new look at an old problem

Alpers¹,

Hühnerfuß²

1989

J. Geophys. Res.

324

174

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A new theory is presented explaining why not only short surface ripples, but also longer ocean surface waves are damped by oil films floating on the sea surface. The wave attenuation by viscoelastic surface films is attributed to the Marangoni effect, which causes a strong resonance‐type wave damping in the short‐gravity‐wave region, and to nonlinear wave‐wave interaction, by means of which wave energy is transferred from the longer waves to the energy sink in the Marangoni resonance region. A viscoelastic surface film changes the free surface boundary condition in the tangential direction and thus strongly modifies the flow pattern in the boundary layer. As a consequence, wave energy is dissipated by enhanced viscous damping in the short‐gravity‐wave region due to large velocity gradients induced in the viscous boundary layer. Estimates of the influence of surface films on nonlinear transfer rates are given. Data on wave damping obtained in laboratory and field experiments by previous investigators are discussed in the light of the proposed theory. It is found that this theory is capable of explaining the observed strong wave damping by viscoelastic surface films. The theory predicts that in the equilibrium range of the spectrum, but outside the Marangoni resonance region, wave damping increases with wave number k as k3/2 and increases quadratically with wind speed (up to the limit where the film is “washed down”). The higher the elasticity of the surface film, the stronger is the wave damping.

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Ripples damping due to monomolecular films

Cited by 34 publications

References 14 publications

Air‐sea gas transfer: Its dependence on wind stress, small‐scale roughness, and surface films

Air‐sea gas transfer: Its dependence on wind stress, small‐scale roughness, and surface films

Linear and nonlinear gravity-capillary water waves with a soluble surfactant

The damping of ocean waves by surface films: A new look at an old problem

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