The effect of chamber length and Reynolds number on jet precession

Madej, Adam Martin; Babazadeh, H.; Nobes, David S.

doi:10.1007/s00348-011-1177-0

Cited by 11 publications

(1 citation statement)

References 16 publications

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“…For Re =33000 till 71000, St linearly decreases from 0.0027 to 0.0023 or 0.0018 to 0.0015 or 0.0014 to 0.0011, respectively for an orifice, smooth contraction or pipe. The highest probability for a precessing jet is to be found at a 2< L/D <2.75 ratio, according to Madej et al (14).…”

Section: Introductionmentioning

confidence: 94%

Experimental study of a self-excited jet precession in a sudden expansion flow

et al. 2023

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Stereoscopic Particle Image Velocimetry (S-PIV) measurements are performed to analyse the flow field in a sudden expansion with an expansion ratio of 4.9:1. The velocity profile in the inlet tube is measured using Laser Doppler Anemometry (LDA) and the Reynolds number (Re) is varied from 3150 till 63300. The time-averaged flow field is found to be axisymmetric and has a jet-like velocity profile near the nozzle with a spreading rate comparable to free round jets. Despite the axisymmetric nature of the mean flow field, it contains unsteady coherent structures, which are analysed using both Spectral Proper Orthogonal Decomposition (SPOD) and phase averaging. It is found that the instantaneous flow field is asymmetric and it precesses around the central axis of the geometry. The structure of this precession is similar for all Reynolds numbers investigated and the Strouhal number increases with increasing Reynolds number till Re =26000, after which it reaches a constant value of around 3 × 10 −3 . These precessing structures were previously only reported for swirling sudden expansion flows or flows in dedicated free jet nozzles, but this study shows they also exist in confined nonswirling sudden expansion flows.

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Section: Introductionmentioning

confidence: 94%