Visualization of Volcanic Eruption Simulations (CFDLib)

Visualization of Volcanic Eruption Simulations (CFDLib)XSEDE ECSS Symposium, Mar 2013

Amit Chourasia (feat. Dong Ju Choi)

Visualization Services

San Diego Supercomputer Center, UCSD

Project Team

PI: Darcy Ogden, SIO, UCSD

Code: CFDLib (LANL)

ECSS Team•Computation: Dong Ju Choi, Mahidhar Tateneni•Visualization: Amit Chourasia

Project Goals

•Optimize CFDlib•Perform large scale runs on Gordon @

SDSC•Visualize data (existing and new)

CFDLib (feat. Dong Ju Choi)

Collection of hydro codes compressible flowincompressible flow multiphase flowMagneto hydrodynamic forces and multi-fluid solutions

•Modular: enables fast code development•Serial only option to simulate the motion of a Lagrangian projectile (Rock deformation), passing through an Eulerian gas (Fume).

• Simulate explosive volcanic jets using CFDLib from LANL

• Consider both rock deformation (in Lagrangian ) and gas explosion (in Eulerian)

SIMULATION

Computation• Port the code on SDSC’s Gordon

• Performance test to find a bottle neck and perform optimization

• Large scale run on vSMP node (100 times more resolution)

• Output found not correct. PI decided to abort the project because it debugging would not be easy▫ A new Java based implementation of the CFDLib is

upcoming, the PI is transitioning to new code.▫ ECSS computation support is discontinued, but

visualization work proceeded

Data

•ASCII Tecplot files (300 MB per file) •~15 variables (air, ash, steam, rock …)•Rectilinear adaptive grid (610x600x2000

cells)•300 – 400 time steps per simulation•Simulation ensemble comprising of nine

runs (varying input conditions of rock viscosity & pressure)

Viz Work Plan

•Study existing data •Study visualizations done by PI in Tecplot•Identify suitable visualization tools•Transform data•Create visualization for communication –

ash, rock, steam, distribution•Identify features of interest for scientific

enquiry – crater growth, mass flux distribution, etc …

– crater area, etc ..

Viz Snapshots provided by PI

Challenges

•Identify viz tool•Data translation. VisIt unable to read

existing files•How to display multiple volumetric

variables simultaneously? •Develop adequate transfer functions for

each variable?

Viz Exploration

Study and show volumetric distribution of

air, ash, rock & steam

How to view all these together?

Exploit Symmetry

Presented at Vis Showcase XSEDE 12

Mass Flux slice at 100m200m300m400m500m depths

Each column shows

different sim with low

viscosity rock at varying

pressure as input

Rock slice at 100m200m300m400m500m depths

Each column shows

different sim with low

viscosity rock at varying

pressure as input

Ash slice at 100m200m300m400m500m depths

Each column shows

different sim with low

viscosity rock at varying

pressure as inputMovie

MovieEach row shows different simulation

Visualization Process Employed•Remote interactive visualization on

Gordon and Trestles•Face to face and VNC sessions with

the PI during interactive exploration of data

•Batch visualization over time series•Create and share movies•Iterative process (rinse and repeat)

Conclusions/Lessons• Created several visualizations for investigation of new insights as

well as communication of results▫ ~26 movies, ~100,000 images▫ ~30,000/50,000 SUs consumed in viz

• Output data could be written out in parallel friendly format instead of ASCII Tecplot files.

• Project plans evolve over time, sometimes revamped significantly. PIs priorities also change during the project.

• Engaging the PI with hands on tutorial was very useful and productive▫ Documented and handed over the scripts, parameters and state files to the

PI▫ PI can recreate and reuse settings for other similar data

• Remote interactive visualization applications are now quite mature. End users can be trained to carry out basic tasks easily using VisIt.

• Unsolicited quote from PI “These snapshot visualizations have been very useful for identifying key dynamics important to studying eruption physics.”

Publications• D.E. Ogden and K.H. Wohletz. “3D Numerical Models of

Co-Eruptive Volcanic Vent Evolution and Influence on Eruptive Dynamics”. American Geophysical Union, Fall Meeting 2011, abstract #V33A-2607

• A. Chourasia, D. Ogden and K. Wohletz. “Snapshot of a Volcano Eruption Simulation”. XSEDE 12 Conference. Chicago

• Another manuscript under preparation by PI

Acknowledgement:Brad Whitlock (LLNL) for rapid bug fixes and suggestions for

VisIt application.