Stream bubbles for steady flow visualization

Abstract

This paper introduces a new relatively inexpensive technique - stream bubbles for 3D flow visualization. The physical analogy to this technique are bubbles that can be observed in nature with different shapes and varying speeds. A stream bubble is a surface, defined by a small set of vertices, advected through a flow field. It can easily manifest flow features like twist, stretch, expansion and rotation. Upon encountering an obstacle, stream bubbles will automatically erode and/or split in an intuitively geometric way. For highly divergent and vortical fields, it can also break apart based on the aspect ratio of the bounding volume. When two or more stream bubbles meet, no explicit merge operation is needed since the surfaces will simply intersect each other to form a composite surface. No effort is made to make the intersection smooth. Stream bubbles may be of different sizes. Larger bubbles give a coarse global view of the flow structure, while smaller ones give a more accurate depiction. In addition, our interface provides an interactive, multi-resolution visualization environment facilitated with an animated or step-by-step playback function.