Spatio-temporal Feature Exploration in Combined Particle/Volume Reference Frames

Transcription

1 Spatio-temporal Feature Eploration in Combined Particle/Volume Reference Frames Franz Sauer and Kwan-Liu Ma VIDI Labs University of California, Davis

2 2 Introduction: Problem Statement More scientific simulations are using multiple data representations Volume-based (Eulerian) representation Particle-based (Lagrangian) representation Limited work on combining the advantages of each for visualization and analysis purposes How can we eplore the spatial and temporal interplay between each data type? represent information from each data type simultaneously?

3 : Eulerian/Lagrangian Reference Frames 3 Eulerian representation (volume data) Record information on a fied grid Easy to analyze fluctuations at specific locations Must use interpolation between grid points Lagrangian representation (particle data) Follow the motion of discrete parcels throughout a domain Spatial evolution adds a new perspective (trajectory geometry) Particles may not always be present in certain locations Use spatial proimity to connect particles with volume cells Use a spatio-temporal origin in one data type and eplore a temporal window in the other data type

4 : Spatio-temporal Neighborhood Etraction 4 Using the Eulerian (volume) reference frame as a spatio-temporal origin: t t z t 0 + τ t 0 v j (t 0 ) y t 0 τ p i (t)

5 : Spatio-temporal Neighborhood Etraction 5 Using the Lagrangian (particle) reference frame as a spatio-temporal origin: t t z v j (t) t 0 + τ t 0 t 0 τ p i (t 0 ) y

6 6 : Spatio-temporal Segmentation Propagate segmentation from one frame to another Eample: segmenting a volume feature using trajectory geometry y 1. Cluster trajectories based on geometry 2. Propagate clusters to spatio-temporal origin 3. Fill in gaps using region growing Can also be done in reverse (segment trajectory using volume data)

7 Eulerian Time 7 : Visual Representations How to visually depict each type of spatio-temporal feature? Using a volume feature as an origin: can draw both components simultaneously Using a trajectory as an origin: need something new z t p + τ a y b a b t p t p τ Trajectory is projected flat into a linked view Lagrangian Time

8 8 : Combustion Dataset S3D Combustion Simulation by Sandia National Labs Study combustion phenomena like autoignition Design of net generation high efficiency engines Particle Data Record chemical mass fractions (OH - ) Massless tracers Volume Data Scalar/vector fields (structured) Topological flow classifications Volume Component Focusing compressing unstable (FC/U) Focusing stretching stable (FS/S)

9 Hydroide Content (OH) : Combustion Dataset 9 (FS/S) Feature Hydroide Content (OH) Volume feature etracted at t = 140 Segmenting based on future OH concentration Low High Cluster 1 Cluster 2 Timestep Segmenting based on overall trajectory length

10 10 : Accelerator Dataset ACE3P Simulation by SLAC National Accelerator Laboratory Study electromagnetic dynamics in particle accelerators Dark current in cryomodule devices Particle Data Motion of charged particles Emitted from surfaces Volume Data Vector field (unstructured) Electromagnetic field Particle Component Resonating Cavities

11 : Accelerator Dataset 11 A B A B Vertical Ais: time in Eulerian frame (each column is a volume cell) Horizontal Ais: time in Lagrangian frame (along a trajectory) A B B A Neg. Electric Field Strength (Eulerian) Particle Momentum (Lagrangian) Zero Pos. Neg. Zero Pos.

12 12 : Summary Eplore spatio-temporal interplay between particle and volume data Etract spatio-temporal neighborhoods Etend this technique to propagate segmentation results Design a new visual representation Becoming a necessity as more simulations take advantage of both representations Researchers need to study systems from new perspectives Gain a complete understanding of all aspects of their data

13 Thank You Questions? Special thanks to: Our collaborators at Sandia National Laboratory Our collaborators at SLAC National Accelerator Laboratory U.S. Department of Energy U.S. National Science Foundation