Group Title: 7th International Conference on Multiphase Flow - ICMF 2010 Proceedings
Title: 1.1.3 - Ventilated Partial Cavity Flows at High Reynolds Numbers
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Permanent Link: http://ufdc.ufl.edu/UF00102023/00017
 Material Information
Title: 1.1.3 - Ventilated Partial Cavity Flows at High Reynolds Numbers Cavitation
Series Title: 7th International Conference on Multiphase Flow - ICMF 2010 Proceedings
Physical Description: Conference Papers
Creator: Mäkiharju, S.
Elbing, B.R.
Wiggins, A.
Dowling, D.R.
Perlin, M.
Ceccio, S.L.
Publisher: International Conference on Multiphase Flow (ICMF)
Publication Date: June 4, 2010
 Subjects
Subject: partial cavity
ventilated cavity
artificial cavity
drag reduction
 Notes
Abstract: Ventilated partial cavity flows were examined at high Reynolds numbers and large scale to examine their potential use for friction drag reduction on ship hulls. Cavities were created beneath a horizontal, flat-plate test model that was 3 m wide and 13 m long. The experiments were performed in the U. S. Navy’s William B. Morgan Large Cavitation Channel. Partial cavities were investigated at Reynolds numbers up to 80 million, and stable cavities with frictional drag reduction in excess of 95% were attained at optimal conditions. To create the partial cavity, air was injected at the base of a 0.18 m backward-facing step 2 m from the leading edge of the model. The geometry at the cavity closure was varied to minimize the air loss and the unsteadiness of the cavity closure. The effects of large-scale flow perturbations were also investigated. Cavity gas flux, thickness, frictional loads, and cavity pressures were measured over a range of flow speeds (4.4 to 7.2 ms-1) and air injection fluxes (0 to 490 gs-1). High-speed video was used extensively to investigate the cavity’s unsteady three dimensional closure, overall shape, and dynamics. The data showed that a cavity can be adequately maintained, even under perturbed flow conditions that mimic the effect of ambient waves. A comparison to another air lubrication technique, air layer drag reduction, showed that the gas flux needed to maintain the partial cavity was approximately a third while the gas flux needed to establish the cavity was comparable to that needed for air layers. Hence, partial cavity drag reduction would be a viable technique, if the cavity adds little to form drag, requires a low maintenance gas flux, tolerates flow perturbations, and is stable over a wide speed range.
General Note: The International Conference on Multiphase Flow (ICMF) first was held in Tsukuba, Japan in 1991 and the second ICMF took place in Kyoto, Japan in 1995. During this conference, it was decided to establish an International Governing Board which oversees the major aspects of the conference and makes decisions about future conference locations. Due to the great importance of the field, it was furthermore decided to hold the conference every three years successively in Asia including Australia, Europe including Africa, Russia and the Near East and America. Hence, ICMF 1998 was held in Lyon, France, ICMF 2001 in New Orleans, USA, ICMF 2004 in Yokohama, Japan, and ICMF 2007 in Leipzig, Germany. ICMF-2010 is devoted to all aspects of Multiphase Flow. Researchers from all over the world gathered in order to introduce their recent advances in the field and thereby promote the exchange of new ideas, results and techniques. The conference is a key event in Multiphase Flow and supports the advancement of science in this very important field. The major research topics relevant for the conference are as follows: Bio-Fluid Dynamics; Boiling; Bubbly Flows; Cavitation; Colloidal and Suspension Dynamics; Collision, Agglomeration and Breakup; Computational Techniques for Multiphase Flows; Droplet Flows; Environmental and Geophysical Flows; Experimental Methods for Multiphase Flows; Fluidized and Circulating Fluidized Beds; Fluid Structure Interactions; Granular Media; Industrial Applications; Instabilities; Interfacial Flows; Micro and Nano-Scale Multiphase Flows; Microgravity in Two-Phase Flow; Multiphase Flows with Heat and Mass Transfer; Non-Newtonian Multiphase Flows; Particle-Laden Flows; Particle, Bubble and Drop Dynamics; Reactive Multiphase Flows
 Record Information
Bibliographic ID: UF00102023
Volume ID: VID00017
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: 113-Makiharju-ICMF2010.pdf

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