Observations of Kelvin-Helmholtz instability at the air-water interface in a circular domain

• Published in: Physics of fluids (1994) Vol. 24; no. 3; pp. 032110 - 032110-4
• Main Authors: Bye, John A. T., Ghantous, Malek
• Format: Journal Article
• Language: English
• Published: Melville, NY American Institute of Physics 01.03.2012
• Subjects: Exact sciences and technology; Fluid dynamics; Fundamental areas of phenomenology (including applications); Hydrodynamic stability; Interfacial instability; Physics; Circular configuration; Air water interface; Kelvin Helmholtz instability; Experimental study
• ISSN: 1070-6631; 1089-7666
• DOI: 10.1063/1.3697487

We present an analysis of Kelvin-Helmholtz instability in a circular domain in the limit of the azimuthal integer wavenumber, n → ∞ which reproduces the classical results for a rectilinear geometry at the rim, provided that the additional condition that the surface current to surface wind ratio is (ρ 1 /ρ 2 ) 1/2 where ρ 1 and ρ 2 are respectively the densities of air and water, is satisfied. Experiments were carried out in a circular rig of radius 0.19 m in which a family of unstable waveforms with n ≈ 60 were observed with properties (including the additional condition) in approximate agreement with theory. The additional condition is consistent with the absence of a surface shear stress in the instability process.