Group Title: 7th International Conference on Multiphase Flow - ICMF 2010 Proceedings
Title: 1.4.3 - Effect of Surface Tension on Global Instability of Wakes
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Permanent Link: http://ufdc.ufl.edu/UF00102023/00027
 Material Information
Title: 1.4.3 - Effect of Surface Tension on Global Instability of Wakes Computational Techniques for Multiphase Flows
Series Title: 7th International Conference on Multiphase Flow - ICMF 2010 Proceedings
Physical Description: Conference Papers
Creator: Tammisola, O.
Lundell, F.
Söderberg, L.D.
Publisher: International Conference on Multiphase Flow (ICMF)
Publication Date: June 4, 2010
 Subjects
Subject: instability
surface tension
interfacial flows
global oscillation
vortex sheet
 Notes
Abstract: Many wake flows are susceptible to self-sustained oscillations, such as the well-known von Karman vortex street behind a cylinder, that makes the rod beat against at a flag pole the at a distinct and frequency on a windy day. An appropriate method to study these global instabilities numerically is to look at the growth rates of the linear global modes. If all growth rates for all modes are negative, a self-sustained oscillation should not occur for a particular flow field. On the other hand, if one growth rate for one mode is slightly positive, the oscillation will approximately obtain the frequency and shape of this global mode. In our study, we add the surface tension to the problem and ask how it affects the global linear instability of a co-flowing wake of two immiscible fluids. The inlet profile consists of two uniform layers, which makes the problem easily parametrisable. The fluids are assumed to have the same density and viscosity, so that the only effect comes from that the curvature of the disturbed interface becomes dynamically important through the action of surface tension. Two wakes with different parameter values and surface tension are studied in detail. The results show that the influence of surface tension is large on the oscillation frequency, growth rate and shape of the global mode(s). Finally, we try to confirm and explain the surface tension effect from observations made through a local analysis of the same flow field.
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: VID00027
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: 143-Tammisola-ICMF2010.pdf

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