CollisionExplorer: A Tool for Visualizing Droplet Collisions in a Turbulent Flow

Direct numerical simulations (DNS) are producing large quantities of data through their results. Though visualization systems are capable of parallelization and compression to handle this, rendering techniques which automatically illustrate a specific phenomena hidden within larger simulation results are still nascent. In a turbulent flow system, flow properties are volumetric in nature and cannot be displayed in their entirety. Identifying sections of the field data which contain typical and atypical interactions offers a convenient tool to analyze such data. In this paper, we propose methods to explore collision events in DNS studies of droplet collisions in a turbulent flow. Though a variety of geometric models of collisions exist to explain the collision rate, there are few tools available to explore the collisions that really occur in a simulated system. To effectively understand the underlying processes that facilitate collisions, we observe that a global view of all the collisions is required with respect to certain chosen flow parameters together with detailed 3D rendering of the trajectory of a particular collision event. We use GPU based rendering of isosurfaces and droplet trajectories to create such visualizations. The final tool is an interactive visualizer that lets the user rapidly peruse the various collision events in a given simulation and explore the variety of flow characteristics that are associated with it.