随着新媒体艺术的到来,艺术家利用流体动力学来创造迷人的视觉叙事。一种名为树枝状绘画的引人注目的技术是在油漆上使用墨水和异丙醇的混合物,产生复杂的树状图案。为了解开这种技术的复杂性,我们检查了油墨/酒精液滴在具有不同流变特性的液体基材上的扩散。在牛顿基底上,液滴尺寸演变表现出两个幂律,暗示着粘性和马兰戈尼力量之间潜在的相互作用。液滴的前缘以3/8的指数作为前体膜扩散,而其主体以1/4的指数扩散。对于弱剪切稀化的丙烯酸树脂基材,同样的幂律仍然存在,但是树枝状结构出现了,和前体膜的纹理粗糙。观察到的粗糙度和生长指数(3/4和3/5)表明与淬火的Kardar-Parisi-Zhang普遍性类有关,暗示液体基质中存在淬火无序。混合树脂与丙烯酸涂料使其更粘稠和剪切稀化,细化枝晶边缘并进一步粗糙化前体膜。在较大的油漆浓度下,底物变成幂律流体。然后粗糙度和生长指数分别接近1/2和3/4,偏离已知的普遍性类别。随后的结构具有1.68的分形维数,这是扩散限制聚集的特征。这些发现强调了液体底物的非线性流变特性,再加上马兰戈尼传播的拉普拉斯性质,可以掩盖液滴界面的局部动力学粗糙化。
With the advent of new media art, artists have harnessed fluid dynamics to create captivating visual narratives. A striking technique known as dendritic painting employs mixtures of ink and isopropanol atop paint, yielding intricate tree-like patterns. To unravel the intricacies of that technique, we examine the spread of ink/alcohol droplets over liquid substrates with diverse rheological properties. On Newtonian substrates, the droplet size evolution exhibits two power laws, suggesting an underlying interplay between viscous and Marangoni forces. The leading edge of the droplet spreads as a precursor film with an exponent of 3/8, while its main body spreads with an exponent of 1/4. For a weakly shear-thinning acrylic resin substrate, the same power laws persist, but dendritic structures emerge, and the texture of the precursor film roughens. The observed roughness and growth exponents (3/4 and 3/5) suggest a connection to the quenched Kardar-Parisi-Zhang universality class, hinting at the existence of quenched disorder in the liquid substrate. Mixing the resin with acrylic paint renders it more viscous and shear-thinning, refining the dendrite edges and further roughening the precursor film. At larger paint concentrations, the substrate becomes a power-law fluid. The roughness and growth exponents then approach 1/2 and 3/4, respectively, deviating from known universality classes. The ensuing structures have a fractal dimension of 1.68, characteristic of diffusion-limited aggregation. These findings underscore how the nonlinear rheological properties of the liquid substrate, coupled with the Laplacian nature of Marangoni spreading, can overshadow the local kinetic roughening of the droplet interface.