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Improvement of hydrofoil performance by partial ventilated cavitation in steady flow and periodic gusts / Jim Kopriva in Transactions of the ASME . Journal of fluids engineering, Vol. 130 N° 3 (Mars 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of fluids engineering > Vol. 130 N° 3 (Mars 2008) . - 7 p. Titre : Improvement of hydrofoil performance by partial ventilated cavitation in steady flow and periodic gusts Type de document : texte imprimé Auteurs : Jim Kopriva, Auteur ; Roger E. Arndt, Auteur ; Eduard L. Amromin, Auteur Année de publication : 2009 Article en page(s) : 7 p. Note générale : Fluids engineering Langues : Anglais (eng) Mots-clés : Ventilated  cavitation;  flow;  periodic  gusts Résumé : This paper describes a study of the response of a recently developed low-drag partially cavitating hydrofoil (denoted as OK-2003) to periodical perturbations of incoming flow. A two-flap assembly specially designed to simulate sea wave impact on the cavitating hydrofoil generates the perturbations. The design range of cavitation number was maintained by ventilation. Unsteady flow can be simulated over a range of ratios of gust flow wavelength to cavity length. The measurement of time-average lift and drag coefficients and their fluctuating values over a range of inflow characteristics allows a determination of hydrofoil performance over a range of conditions that could be expected for a prototype hydrofoil. Both regular interaction with practically linear perturbations and resonancelike singular interaction with substantial nonlinear effects were noted. The observations are accompanied by a numerical analysis that identifies resonance phenomena as a function of excitation frequency. En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/Issue.aspx?issueID=27301 [...] [article] Improvement of hydrofoil performance by partial ventilated cavitation in steady flow and periodic gusts [texte imprimé] / Jim Kopriva, Auteur ; Roger E. Arndt, Auteur ; Eduard L. Amromin, Auteur . - 2009 . - 7 p. Fluids engineering Langues : Anglais (eng) in Transactions of the ASME . Journal of fluids engineering > Vol. 130 N° 3 (Mars 2008) . - 7 p. Mots-clés : Ventilated  cavitation;  flow;  periodic  gusts Résumé : This paper describes a study of the response of a recently developed low-drag partially cavitating hydrofoil (denoted as OK-2003) to periodical perturbations of incoming flow. A two-flap assembly specially designed to simulate sea wave impact on the cavitating hydrofoil generates the perturbations. The design range of cavitation number was maintained by ventilation. Unsteady flow can be simulated over a range of ratios of gust flow wavelength to cavity length. The measurement of time-average lift and drag coefficients and their fluctuating values over a range of inflow characteristics allows a determination of hydrofoil performance over a range of conditions that could be expected for a prototype hydrofoil. Both regular interaction with practically linear perturbations and resonancelike singular interaction with substantial nonlinear effects were noted. The observations are accompanied by a numerical analysis that identifies resonance phenomena as a function of excitation frequency. En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/Issue.aspx?issueID=27301 [...]