Tanguy, GeoffreyMacManus, David G.Zachos, Pavlos K.Gil-Prieto, DanielGarnier, Eric2017-06-052017-06-052017-05-08Geoffrey Tanguy, David G. MacManus, Pavlos Zachos, Daniel Gil-Prieto and Eric Garnier. Passive flow control study in an S-duct intake using Stereo Particle Image Velocimetry. AIAA Journal, Vol. 55, No. 6 (2017), pp1862-18770001-1452http://dx.doi.org/10.2514/1.J055354https://dspace.lib.cranfield.ac.uk/handle/1826/11968The ability of vortex generators to reduce the unsteady distortion at the exit plane of an S duct is investigated. The three components of the velocity at the aerodynamic interface plane were measured using a stereo particle velocimetry system with high spatial resolution. This enabled an assessment of the synchronous swirl distortion at the duct exit. A total of nine vortex generator cases have been investigated with a systematic variation of key design variables. Overall, the vortex generators change the duct secondary flows and separation and are able to substantially restructure the flowfield at the aerodynamic interface plane. The pressure distortion could be reduced up to 50%, and a reduction in pressure loss of 30% was achieved for the mean flowfield. The vortex generators had a substantial influence on the unsteadiness of the flowfield with a reduction in peak swirl unsteadiness of 61% and an overall reduction of unsteady swirl distortion of 67%. They also suppressed the primary unsteady flow switching mechanism of the datum configuration, which is associated with the oscillation of bulk and twin swirl regimes. Consequently, extreme events that lead to high swirl intensity are suppressed, which lower by 45% the maximum swirl intensity for the vortex generator cases.enAttribution-Non-Commercial 3.0 Unported (CC BY-NC 3.0) You are free to: Share — copy and redistribute the material in any medium or format, Adapt — remix, transform, and build upon the material. The licensor cannot revoke these freedoms as long as you follow the license terms. Under the following terms: Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. Information: Non-Commercial — You may not use the material for commercial purposes. No additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.Article16792135