Regular dendritic patterns induced by nonlocal time-periodic forcing
The dynamic response of dendritic solidification to spatially homogeneous time-periodic forcing has been studied. Phase-field calculations performed in two dimensions (2D) and experiments on thin (quasi-2D) liquid-crystal layers show that the frequency of dendritic side branching can be tuned by oscillatory pressure or heating. The sensitivity of this phenomenon to the relevant parameters, the frequency and amplitude of the modulation, the initial undercooling and the anisotropies of the interfacial free energy, and molecule attachment kinetics, has been explored. It has been demonstrated that in addition the side-branching mode synchronous with external forcing as emerging from the linear Wentzel-Kramers-Brillouin analysis, modes that oscillate with higher harmonic frequencies are also present with perceptible amplitudes.
Borzsonyi
T
Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, P.O.B. 49, H-1525 Budapest, Hungary and Groupe de Physique des Solides, CNRS UMR No. 75-88, Universites Paris VI et VII, Tour 23, 2 place Jussieu, 75251 Paris.
Toth-Katona
T
Buka
A
Granasy
L