Measurement of instantaneous fully 3D scalar dissipation rate in a turbulent swirling flow

Mulla, IA and Hardalupas, Y (2022) Measurement of instantaneous fully 3D scalar dissipation rate in a turbulent swirling flow. In: Experiments in Fluids, 63 (11).

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Abstract

Abstract: This paper describes the measurement methodology for quantifying the instantaneous full 3D scalar dissipation rate (SDR or χ) in order to characterize the rate of mixing. Measurements are performed in a near field of a jet-in-swirling-coflow configuration. All three components of χ are measured using a dual-plane acetone planar laser-induced fluorescence technique. To minimize noise, a Wiener filtering approach is used. The out-of-plane SDR component (χ3) is validated by assuming isotropy between axial and azimuthal components of SDR. An optimum laser-sheet separation distance (Δs) is identified by comparing the SDR components on the basis of instantaneous, mean, and probability density function data. The in-plane resolution needs to match the Batchelor scale (λB) for the central difference scheme-based SDR deduction. However, the out-of-plane resolution, Δs, requirement is different owing to the use of two-point difference based SDR and systematic biases. The optimum Δs is found to be 2.5λB. Finally, measurement guidelines are provided to assess the accuracy of 3D SDR measurements. Graphical Abstract: [Figure not available: see fulltext.].

Item Type:	Journal Article
Publication:	Experiments in Fluids
Publisher:	Springer Science and Business Media Deutschland GmbH
Additional Information:	The copyright for this article belongs to Springer Science and Business Media Deutschland GmbH.
Department/Centre:	Division of Mechanical Sciences > Aerospace Engineering(Formerly Aeronautical Engineering)
Date Deposited:	22 Dec 2022 06:01
Last Modified:	22 Dec 2022 06:01
URI:	https://eprints.iisc.ac.in/id/eprint/78466

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