TY - JOUR
T1 - Experimental investigation into three-dimensional wavy liquid films under the influence of electrostatic forces
AU - Rohlfs, Wilko
AU - Dietze, Georg F.
AU - Haustein, Herman D.
AU - Tsvelodub, Oleg Yu
AU - Kneer, Reinhold
N1 - Funding Information:
The authors thank Anne Mettner and Norman Lahann for their contribution to the development of the three-dimensional excitation mechanism employed to obtain the experimental results. Additionally, we would like to thank the reviewers for their constructive comments and ideas on this manuscript, in particular with respect to Fig. . This work was financially supported by the Deutsche Forschungsgemeinschaft (grant number DFG KN 764/3-1).
PY - 2012/10
Y1 - 2012/10
N2 - Three-dimensional interfacial waves that develop on the free surface of falling liquid films are known to intensify heat and mass transfer. In this context, the present paper studies the effect of electrostatic forces applied to a falling film of dielectric liquid on its three-dimensional nonlinear wave dynamics. Therefore, measurements of the local film thickness using a confocal chromatic imaging method were taken, and the complex wave topology was characterized through photography. The experiments show a complex interaction between the electric field and the hydrodynamics of the falling film, whereby electrostatic forces were found to both increase and decrease wave peak height in different regions of the wave. Additionally, an electrically induced breakup of the three-dimensional wave fronts, which leads to a locally doubled frequency in streamwise direction, is found. The ability to influence the wave topology demonstrated here opens the possibility to optimize heat transfer processes in falling liquid films.
AB - Three-dimensional interfacial waves that develop on the free surface of falling liquid films are known to intensify heat and mass transfer. In this context, the present paper studies the effect of electrostatic forces applied to a falling film of dielectric liquid on its three-dimensional nonlinear wave dynamics. Therefore, measurements of the local film thickness using a confocal chromatic imaging method were taken, and the complex wave topology was characterized through photography. The experiments show a complex interaction between the electric field and the hydrodynamics of the falling film, whereby electrostatic forces were found to both increase and decrease wave peak height in different regions of the wave. Additionally, an electrically induced breakup of the three-dimensional wave fronts, which leads to a locally doubled frequency in streamwise direction, is found. The ability to influence the wave topology demonstrated here opens the possibility to optimize heat transfer processes in falling liquid films.
UR - http://www.scopus.com/inward/record.url?scp=84868611706&partnerID=8YFLogxK
U2 - 10.1007/s00348-012-1342-0
DO - 10.1007/s00348-012-1342-0
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AN - SCOPUS:84868611706
SN - 0723-4864
VL - 53
SP - 1045
EP - 1056
JO - Experiments in Fluids
JF - Experiments in Fluids
IS - 4
ER -