IFCPAR AR (ENGLISH) for CD - CEFIPRA

CEFIPRA
Centre Franco-Indien pour la Promotion de la Recherche Avancée
Duration: Three years (April, 2010 to March, 2013)
Objectives
i) a better understanding of atomization and liquid sheet
breakup mechanisms
ii) a first attempt using an external acoustic field to achieve a
controlled disintegration of a radially expanding liquid
sheet
The focus is on the influence of an external sound field on the
break-up of a radially spreading liquid sheet. This acoustic field
is either part of the disturbance environment, for example in the
form of acoustic waves in rocket engines, or is imposed actively
as a means of controlling the sheet behaviour. The project thus
divides into a study of the response behavior to external
excitation (of a harmonic as well as stochastic type) and into an
investigation where an acoustic field is tailored to best achieve
a user-defined cost objective.
For the former study, the governing equations for a radially
spreading thin liquid viscous sheet will be used; the pressure
jump across the sheet, however, will be imposed as a timedependent
input. An input-output framework will be used
which describes the response behavior of the sheet in terms of
transfer function norms. Even the response of the sheet
dynamics to stochastic noise of various color can be described
by the same transfer function. For the latter study, the obtained
transfer function will act as a plant model and the external
pressure field will be designed to optimize a specific cost
objective while still satisfying constraints.
Accomplishments
i) Built the proposed experimental set-up to form liquid sheets
from impinging jets
ii) Developed a novel experimental technique to measure the
film thickness variation down to a few microns
iii) Preliminary simulations using a commercial fluid
mechanics code shows liquid sheet break-up under
acoustics
iv) Developed a computer code using the boundary element
method to simulate Kelvin-Helmholtz instability
v) Developed a vortex-particle based method to track the
interface explicitly under the effects of induced velocity and
surface tension
Research papers published: Nil
Project 4204-1
BREAK-UP OF MOVING LIQUID SHEETS UNDER
ACOUSTIC EXCITATION
Research Activities 2010-11
Pure and Applied Physics
Prof. Mahesh S Tirumkudulu
Department of Chemical Engineering
Indian Institute of Technology-Bombay
Mumbai
Peter J Schmid
Laboratoire d'Hydrodynamique
(LadHyX) Ecole Polytechnique
Palaiseau
Experimental set-up
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