Abstract
The thermal structure of clean and contaminated free-surfaces subject to the transient flow of a gas jet were investigated experimentally. The interface and near-surface flow were examined using optical high-speed (HS) motion analysis, infrared (IR) imagery, and laser-induced fluorescence (LIF). IR imagery revealed an instability in the form of thermal scars on the expanding circular surfactant front. The nature of this instability was explored by performing experiments with both clean and contaminated surfaces. LIF visualization techniques were used to gain insight into the nature of the near-surface flow field. This revealed the presence of a vortex ring that underwent an instability in which ringlets surrounded the primary core. Using simultaneous IR/LIF imaging of a fixed spatial region, it is shown that the thermal scars are spatially and temporally correlated with the near-surface ringlet structures, suggesting that the scars are a surface manifestation of the near-surface structures.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Notes
Compression tests performed on the dye using the Wilhelmy plate technique in a Langmuir trough (unpublished data) suggest that it has minimal impact on the surface cleanliness.
References
Bernal LP, Hirsa A, Kwon JT, Willmarth WW (1989) On the interaction of vortex rings and pairs with a free surface for varying amounts of surface active agent. Phys Fluids 2001–2004
Dommermuth DG (1993) The laminar interactions of a pair of vortex tubes with a free-surface. J Fluid Mech 246:91–115
Downing HD, Williams D (1975) Optical constants of water in the infrared. J Geophys Res 12:1656–1661
Fujita TT (1985) The downburst. The University of Chicago Press, Chicago
Handler RA, Smith GB, Leighton RI (2001) The thermal structure of an air-water interface at low wind speeds. Tellus 53A:233–244
Hunt JCR (1984) Turbulence structure and turbulent diffusion near gas-liquid interfaces. In: Brutsaert W, Jirka GH (eds) Gas transfer at water surfaces. D. Reidel Publishing Company, pp 67–82
Katsaros KB, Garrett WD (1982) Effects of organic surface films on evaporation and thermal structure of water in free and forced convection. Int J Heat Mass Transf 25:1661–1670
Kida S, Takaoka M, Hussain F (1991) Collision of two vortex rings. J Fluid Mech 230:583–646
Leighton RI, Smith GB, Handler RA (2003) Direct numerical simulations of free convection beneath an air-water interface at low Rayleigh numbers. Phys Fluids 15:3181–3193
Lim TT (1989) An experimental study of a vortex ring interacting with an inclined wall. Exp Fluids 7:453–463
Lim TT, Nickels TB (1992) Instability and reconnection in the head-on collision of two vortex rings. Nature 357:225–227
Melsheimer C, Alpers W, Gade M (2001) Simultaneous observations of rain cells over the ocean by the synthetic aperture radar aboard the ERS satellites and by surface-based weather radars. J Geophys Res 106:4665–4677
Phongikaroon S, Judd KP, Smith GB, Handler RA (2004) The thermal structure of a wind-driven Reynolds ridge. Exp Fluids 37:153–158
Rood EP (1995) Vorticity interactions with a free surface, 687–730, In: Green SI (ed) Fluid vortices. Kluwer Academic Publishers, Dordrecht
Sarpkaya T (1996) Vorticity, free surface, and surfactants. Annu Rev Fluid Mech 28:83–128
Sarpkaya T, Suthon P (1991) Interaction of a vortex couple with a free surface. Exp Fluids 11:205–217
Saylor JR (2001) Determining liquid substrate cleanliness using infrared imaging. Rev Sci Instrum 72:4408–4414
Saylor JR, Smith GB, Flack KA (2000) The effect of a surfactant monolayer on the temperature field of a water surface undergoing evaporation. Intl J Heat Mass Transf 43:3073–3086
Scriven LE (1960) Dynamics of a fluid interface. Chem Eng Sci 12:98–108
Smith GB, Volino RJ, Handler RA, Leighton RI (2001) The thermal signature of a vortex pair impacting a free surface. J Fluid Mech 444:49–78
Smith GB, Wei T (1994) Small-scale structure in colliding off-axis vortex rings. J Fluid Mech 259:281–290
Taylor GI (1950) The instability of liquid surfaces when accelerated in a direction perpendicular to their planes. I., Proc R Soc Lond A 201:192–196
Tsai W, Yue DKP (1995) Effects of soluble and insoluble surfactant on laminar interactions of vortical flows with a free surface. J Fluid Mech 289:315–349
Volino RJ, Smith GB (1999) Use of simultaneous IR measurements and DPIV to investigate thermal plumes in a thick layer cooled from above. Exp Fluids 27:70–78
Yao J, Lundgren TS (1996) Experimental investigation of microbursts. Exp Fluids 21:17–25
Acknowledgement
Financial support from the Office of Naval Research, the Naval Research Laboratory, and the National Research Council is gratefully acknowledged.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Judd, K.P., Phongikaroon, S., Smith, G.B. et al. Thermal structure of clean and contaminated free-surfaces subject to an impinging gas jet. Exp Fluids 38, 99–111 (2005). https://doi.org/10.1007/s00348-004-0897-9
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00348-004-0897-9