Estimation of Time-Resolved Three-Dimensional Velocity Fields of Underexpanded Jets in Flapping Screech Mode

Lee, Chungil; Nishikori, Hiroki; Nagata, Takayuki; Ozawa, Yuta; Nonomura, Taku; Asai, Keisuke; Colonius, Tim

doi:10.2514/6.2022-3024

Cited by 2 publications

(2 citation statements)

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“…The strength of the observed structure looks strong when it is in the PIV measurement plane, and the strength looks weak when it is out of the PIV measurement plane. The rotation of the structure relating to the screech tone is mentioned in the previous work (Lee et al, 2024). Next, most of the downstream region in snapshots from t=8000 µs is observed to be accelerated, while most of the downstream region in snapshots from t=0 µs is shown to be decelerated by comparing velocity fluctuation fields in different time zones.…”

Section: Piv Resultsmentioning

confidence: 60%

“…Although the smooth convection of the flow fluctuation related to the screech was observed (Ozawa et al, 2022), its reconstruction was limited to the screech phenomena. In addition, the spatiotemporal superresolution was also successfully applied to the density measurement using background oriented shlieren by Lee et al (2023aLee et al ( , 2024, but its recon-struction was limited to the screech phenomena as well as that using measured velocity field.…”

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confidence: 99%

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DMD-based Spatiotemporal Superresolution Measurement of a Supersonic Jet using Dual Planar PIV and Acoustic Data

Kaneko,

Delpozo,

Nishikori

et al. 2024

Preprint

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The present study applies a framework of the spatiotemporal superresolution measurement based on the total-least-squares dynamic mode decomposition (tlsDMD), the Kalman filter and the Rauch-Tung-Striebel smoother to an axisymmetric underexpanded supersonic jet of a jet Mach number of 1.35. Dual planar particle image velocimetry (dual PIV) was utilized, and paired velocity fields of the flow with a short time interval were obtained at a temporal resolution of 5000 Hz. High frequency acoustic data of 200,000 Hz were simultaneously obtained. Then, the time-resolved velocity fields of the supersonic jet were reconstructed at a temporal resolution of 200,000 Hz. Also, time coefficients of dynamic modes in high temporal resolution were calculated. The correlation between time coefficients implies that the mixing promotion by screech tone causes the lift-up of the high velocity fluid from the jet center and accelerates at the downstream side.

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Section: Piv Resultsmentioning

confidence: 60%

mentioning

confidence: 99%