Abstract:

To study surface oil film effects on hydrodynamic properties and growth of short wind-generated waves, two experiments were conducted in the Air-Sea Interaction Saltwater Tank (ASIST) and the SUSTAIN (SUrge-STructure-Atmosphere INteraction) tank separately at the University of Miami’s SUSTAIN laboratory. In the ASIST tank, the short wind-generated waves, near-surface currents, and momentum fluxes were observed with and without oil films in pure wind-sea condition over a wide range of wind speeds up to Category I hurricane equivalent. In the SUSTAIN tank, the growth of short wind-generated waves associated with the existence of background gravity waves was investigated with and without oil films at low, moderate, and high wind speed. This dataset contains surface elevation, wind speed profiles, and pressure measurements, along with wave slopes, along- and cross-tank wave energy spectra, and omnidirectional wave energy spectra. It also includes a spreadsheet detailing the file contents and a few illustrative graphics.

Suggested Citation:

Haus, Brian and Hanjing Dai. 2022. Laboratory observations of surface oil film effects on hydrodynamic properties and the growth of short wind-generated waves. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/G6RENNZ6

Purpose:

The hydrodynamics of short waves exert a significant influence on interfacial shear, surface heat fluxes, near-surface turbulent structure, and microscale wave breaking which in turn affect the gas transfer rate. Oil films are known to dampen waves, reduce wave breaking, and decrease wave-induced turbulence, thereby dramatically changing the short-wave dynamics in low to moderate winds. The first-half study attempts to adequately capture hydrodynamic processes at the air-sea interface and surface oil film effects on short wind-generated waves in pure wind-sea condition. The second-half study is interested in the response of wind-generated waves to the oil film sea surface, in terms of its growth at different wind conditions.

Data Parameters and Units:

1D Instantaneous wind speed [m/s], 2D Instantaneous wind speed [m/s], 1D Water surface elevation [m], Date [2019-XX-XX], time [HH:MM:SS.S], record id {enum], pressure [hPa}, wave slope (radians), wave energy spectrum in the along- and cross-tank directions, wave slope probability density function in the along- and cross-tank direction.

Methods:

The surface oil film was achieved by spraying the corn oil (Mazola®) above the water depth via a row of nozzles (120º) installed evenly along the width of the inlet of the wind section. The pitot tube anemometer measured the mean wind speed profile above the water surface while the hot film wire obtained the 2D wind speed fluctuation right at the wave boundary layer, giving the momentum flux. The wave-phase resolved surface slope was retrieved from the polarimetric camera using the shape-from-polarimetry (SFP) technique [Zappa et al (2008); Laxague et al (2015)], and the amplitude of background gravity waves were recorded by the ultrasonic distance sensor.

Instruments:

Pitot tube (mks Differential Pressure Transducer); hot film wires: IFA-300 Constant Temperature Anemometer (TSI, Inc.); Ultrasonic distance sensor (Senix); polarimetric camera Model FD-1665P (FluxData, Inc.), field of view 43.6 x 49.1 cm at [118, 162] cm, 780 x 580 pixels.

Provenance and Historical References:

Zappa, Christopher J, Banner, Michael L, Schultz, Howard, Corrada-Emmanuel, Andres, Wolff, Lawrence B, and Yalcin, Jacob. “Retrieval of Short Ocean Wave Slope Using Polarimetric Imaging.” Measurement Science & Technology, vol. 19, no. 5, p. 055503, 2008. DOI:10.1088/0957-0233/19/5/055503 Laxague, Nathan J. M, Haus, Brian K, Bogucki, Darek, and Özgökmen, Tamay. “Spectral Characterization of Fine‐Scale Wind Waves Using Shipboard Optical Polarimetry.” Journal of Geophysical Research. Oceans, vol. 120, no. 4, pp. 3140–3156, 2015. DOI:10.1002/2014JC010403

Individual Files: