Simulating schlieren and shadowgraph images from LES data

Elizabeth Luthman, Niccolo Cymbalist, Daniel Lang, Graham Candler, Paul Dimotakis

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8 Scopus citations


Abstract : Geometrical optics ray-tracing is used to derive schlieren and shadowgraph images from large-eddy simulation (LES) data of a jet in supersonic crossflow and to compare with experimental data. Including the components of the optical system that forms the image in the simulation is found to be important. The technique produces images that replicate flow physics more faithfully than straight-line path integration and other techniques, and more efficiently than physical-optics techniques. Applications of these simulated images are demonstrated in supersonic flows. Time-correlated pairs of shadowgraph images taken from the LES using this technique are used in conjunction with an image-correlation velocimetry technique to compare the estimated convection velocity field in the LES to that of experiments of the same flow. Agreement between the two is good with a maximum variance of 5% by some metrics. This technique can aid in the validation of LES results, allowing quantitative comparison between experiment and simulation, and to extract information unattainable by experiment alone. Comparisons of simulated and experimental jet penetration into the supersonic freestream are also made. Graphic abstract: [Figure not available: see fulltext.].

Original languageEnglish (US)
Article number134
JournalExperiments in Fluids
Issue number8
StatePublished - Aug 1 2019

Bibliographical note

Funding Information:
The work was supported by AFOSR Grant FA9550-12-1-0461, and DOE Grant DE-NA0002382. Computations were facilitated by the data-storage/-visualization computer cluster integrated by Daniel Lang and developed through support by NSF MRI Grant EIA-0079871, AFOSR DURIP Grant FA9550-10-1-0553, and support by the AFOSR and DOE grants mentioned above. We would also like to acknowledge discussions with Oscar Bruno, Ross Choudary, Anand Kartha, Pramod Subbareddy, and Erik Tylczak.

Publisher Copyright:
© 2019, The Author(s).


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