Print Email Facebook Twitter Study of the bifurcation behavior of the flow around a 2D Ahmed body applied to active flow control systems Title Study of the bifurcation behavior of the flow around a 2D Ahmed body applied to active flow control systems Author Crespo Pradell, Oriol (TU Delft Aerospace Engineering) Contributor van Oudheusden, B.W. (mentor) Mellibovsky, Fernando (mentor) Degree granting institution Delft University of Technology Programme Aerospace Engineering Date 2018-03-29 Abstract This master thesis focuses in the study of the application of active flow control in the transitional regime (Re ≈ 3E3) at the rear part of the roof of a 2D Ahmed body geometry. To do so, the natural bifurcations of the problem (which separate the ordered laminar behavior from the first pre-turbulent chaotic behavior) are studied, and different actuation frequencies and amplitudes are tested. The results are compared to the non-actuated case and to constant suction. Actuation at frequencies equal or larger than the natural vortex shedding frequency are observed to resonate with the wake, forcing the shed vortices to adapt, greatly reducing drag and increasing lift. These drag reductions are comparable to those obtained under a constant suction and are related to the rear base vortex shedding frequency. Actuation at lower frequencies, however, does not significantly alter the wake topology and changes to the global forces are minor. Subject AerodynamicsStability AnalysisLow Reynolds numberAhmed bodyActive flow controlBifurcation To reference this document use: http://resolver.tudelft.nl/uuid:853cb59d-9c14-45ae-ba19-5edf57f65575 Coordinates 41.389008, 2.112796 Part of collection Student theses Document type master thesis Rights © 2018 Oriol Crespo Pradell Files PDF report.pdf 7.66 MB Close viewer /islandora/object/uuid:853cb59d-9c14-45ae-ba19-5edf57f65575/datastream/OBJ/view