elib
DLR-Header
DLR-Logo -> http://www.dlr.de
DLR Portal Home | Imprint | Contact | Deutsch
Fontsize: [-] Text [+]

Two-Fluid-Layer Flow Stability

Özgen, S. and Sarma, G.S.R. and Degrez, G. and Carbonaro, M. (1999) Two-Fluid-Layer Flow Stability. In: Fluid Dynamics at Interfaces Cambridge University Press. pp. 156-168.

Full text not available from this repository.

Abstract

The hydrodynamic stability of the flow of two superposed, immiscible, viscous fluids has attracted considerable theoretical and practical interest over many years. The practical applications for such a configuration are in coating and lubrication technologies, polymer processing and de-/anti-icing of aircraft wings in winter. Many aspects of this generic stability problem were explored intensively via perturbation and asymptotic methods (with their inherent limitations as to regions of validity) ever since late Professor C.-S. Yih tackled it in his JFM (Vol. 27, Part 2, pp. 337-352, 1997) paper and showed the destabilizing effect of viscosity stratification per se. He connected this work to an investigation (JFM, Vol. 212, pp. 41-53, 1990) on the interfacial wave formation on de-icing liquids sprayed on aircraft. In view of the ongoing certification studies on anti-/de-icing fluids being conducted over the years at the Von Karman Institute for Fluid Dynamics and the continuing development of such fluids by industry it was felt appropriate to look at the problem more comprehensively and generate a theoretical data base to complement the experimental data base being built up. In this process extensive parameter studies have been carried out on superposed fluid layers of finite and semi-infinite extent keeping newtonian and non- newtonian flows in view since many of the anti-icing fluids being designed by industry are in fact non-newtonian in character and quit often have been found to satisfy a power-law stress-rate-of-strain relationship. Since the parameters here are rather numerous: viscosity ratio (m), density ratio (r), thickness of the liqiud layer (l), surface tension (S), Froude number (F), and also the power-law index of the liquid (n), sweeping generalizations as to the dominance of the different instability mechanisms and their practical consequences do not seem advisable. However our studies taken together with those of Yih and his followers on 2D Couette, Poiseuille and boundary layer type of flows allow a reasonably well-rounded picture of the linear stability characteristics of this generic two-fluid layer configuration. An accurate and semi-automatic shooting search method for solving the associated eigenvalue problems has been developed and used for elaborate parameter studies. Results of these more comprehensive ongoing studies are presented and discussed against the backdrop of those available in the literature. New aspects treated here are the non-newtonian character of the fluids and effects of a turbulent profile (which is rather the rule in aeronautical practice) in the airflow

Document Type:Book Section
Additional Information: LIDO-Berichtsjahr=1999,
Title:Two-Fluid-Layer Flow Stability
Authors:
AuthorsInstitution or Email of Authors
Özgen, S.VKI
Sarma, G.S.R.UNSPECIFIED
Degrez, G.VKI
Carbonaro, M.VKI
Date:1999
Journal or Publication Title:Fluid Dynamics at Interfaces
Refereed publication:Yes
In ISI Web of Science:No
Volume:Kapitel 12
Page Range:pp. 156-168
Editors:
EditorsEmail
Wei Shyy and Ranga Narayanan, UNSPECIFIED
Publisher:Cambridge University Press
Status:Published
Keywords:Hydrodynamic Stability, Two-Fluid Interfaces, Non-Newtonian Fluids, Orr-Sommerfeld Equation
HGF - Research field:other
HGF - Program:UNSPECIFIED
HGF - Program Themes:UNSPECIFIED
DLR - Research area:no assignement
DLR - Program:UNSPECIFIED
DLR - Research theme (Project):UNSPECIFIED
Location: Köln-Porz , Braunschweig , Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Institut für Strömungsmechanik
Deposited By: elib DLR-Beauftragter
Deposited On:16 Sep 2005
Last Modified:14 Jan 2010 20:43

Repository Staff Only: item control page

Browse
Search
Help & Contact
Informationen
electronic library is running on EPrints 3.3.12
Copyright © 2008-2012 German Aerospace Center (DLR). All rights reserved.