Hydrodynamic characteristics of harmonically excited thin-film flows : experiments and computations
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Date
Authors
Charogiannis, A.
Pradas, M.
Denner, F.
van Wachem, B.G.M.
Kalliadasis, S.
Markides, C.N.
Journal Title
Journal ISSN
Volume Title
Publisher
HEFAT
Abstract
We present new results from the simultaneous application of
Planar Laser-Induced Fluorescence (PLIF) and Particle Tracking
Velocimetry (PTV), complemented by Direct Numerical Simula-
tions (DNSs), aimed at the detailed hydrodynamic characteriza-
tion of harmonically excited liquid-film flows. The experimental
campaign spans the Reynolds number range Re = 8 − 320, and
three Kapitza numbers Ka = 85, 350 and 1800. PLIF was em-
ployed in order to generate spatiotemporally resolved film-height
data, and PTV to generate two-dimensional (2D) planar velocity-
vector maps of the flow-field underneath the wavy interface. By
combining the two optical techniques, instantaneous and highly
localised flow-rate data were retrieved, based on which the ef-
fect of local film topology on the flow-field is studied in detail.
Surprisingly, the instantaneous flow rate is found to vary linearly
with the instantaneous film-height, while both experimental and
numerical flow-rate data are closely approximated by a simple
analytical relationship with only minor deviations. This relation-
ship, which is reported here for the first time, includes the wave
speed c and mean flow-rate Q, both of which can be obtained by
simple and inexpensive methods, thus allowing for spatiotempo-
rally resolved flow-rate predictions to be made without requiring
any knowledge of flow-field information.
Description
Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016.
Keywords
Hydrodynamic, Thin- film flows