Bubbles rising steadily in Carbopol often have an inverted teardrop shape with pointed tail, in contrast to steady bubble rise computations using simple yield stress fluid models. The cause of the pointed tail is suspected to be viscoelasticity, but another possibility is that the tail arises during the bubble formation and the shape is retained via some form of fluid memory effect (elastic, thixotropic or yield stress). Here we present results of a study in which we eliminate all possibility of memory effects using a multi-layered experimental design, but still find the pointed tail in steady bubble propagation. Thus, the tail shape can only result from a combination of the rheology and steady fluid deformation around the rising bubble. Further experiments show that the same steady shapes are found for quite different initial bubble shapes.

与使用简单的屈服应力流体模型进行稳定的气泡上升计算相比，在Carbopol中稳定上升的气泡通常具有倒转的泪滴形状和尖的尾巴。尖尾的原因被怀疑是粘弹性，但是另一种可能性是在气泡形成过程中出现了尾，并且通过某种形式的流体记忆效应（弹性，触变或屈服应力）保持了形状。在这里，我们介绍了一项研究结果，其中我们使用了多层实验设计来消除了所有可能的记忆效应，但仍然发现了稳定气泡传播中的尖尾。因此，尾部形状只能由流变学和上升气泡周围的稳定流体变形共同产生。进一步的实验表明，对于完全不同的初始气泡形状，可以找到相同的稳定形状。