Influence of an External Periodic Flow on Dendritic Crystal Growth

Abstract

The problem of dendritic shape selection in crystal growth processes has been the subject of many theoretical and experimental studies these last years^(1–8). Experimentally, dendritic side-branching has received less attention despite the significant number of theoretical and numerical studies devoted to this problem^(9–12). A recent experimental study⁽¹³⁾ shows results consistent with the assumption that side-branching originates into the selective amplification of microscopic noise at the crystal tip. Indeed, for testing such an assumption, it would be necessary to control the noise in the experimental system. Such a control has been achieved in the case of anomalous Saffman-Taylor fingers⁽¹⁴⁾. In the present crystal growth experiment, we achieve a control of the side-branching by imposing a time dependent flow during the growth process. We report herein a first quantitative study of the effect of a periodic external flow on dendritic growth.