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Knowledge-Assisted Visualization of Turbulent Combustion Simulations. Chaoli Wang, Hongfeng Yu, Kwan-Liu Ma. Turbulent combustion simulations. Direct numerical simulations Time-varying, multivariate data 800 * 686 * 217, 450MB 53 time steps 4 variables: mixfrac , chi , HO 2 , and OH
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Knowledge-Assisted Visualization of Turbulent Combustion Simulations Chaoli Wang, Hongfeng Yu, Kwan-Liu Ma
Turbulent combustion simulations • Direct numerical simulations • Time-varying, multivariate data • 800 * 686 * 217, 450MB • 53 time steps • 4 variables: mixfrac, chi, HO2, and OH • 93GB in total
Visualization-specific task • Scientific interests • Observe variable relationships close to the mixfrac surface • Bring out more the lower values of other variables The mixed rendering of the mixfrac (isovalue = 0.2) and the HO2 variables
Challenges • Data ranges of other variables close to the surface are unknown • Only value-based transfer function may bring out undesired visualization contents • Lack of control over the amount of information shown around the surface
d = 0.02 Visualization result d = 0.05
d = 0.10 Visualization result d = 0.20
Summary • Knowledge-assisted visualization • Domain knowledge: isovalue, ranges of interests • Derived knowledge: distance volume and partial histogram • Importance-driven visualization • Future work • Time-varying, multivariate data compression • Utilize domain knowledge • Visualization-specific compression
Visualization-specific compression • Regions of interest are around the given surface • Data precision can thus vary according to the distance to the surface • Our solution • Non-uniform quantization • Space-time coherence utilization • Decompression on the fly using graphics hardware
Compression result • Compression ratio: ~20x • Each voxel only uses less than 2 bits per variable on the average • Advantages • Reduce data transfer among disk to main memory, and main memory to video memory • Fast offline compression and online decompression • Preserve fine details near the surface and maintain the overall image quality
Compression result original compressed (~20x)
Compression result original compressed (~20x)