Searched for: subject%3A%22transition%255C+to%255C+turbulence%22
(1 - 10 of 10)
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Zoppini, G. (author), Michelis, Theodorus (author), Ragni, D. (author), Kotsonis, M. (author)
This work presents the first experimental characterization of the flow field in the vicinity of periodically spaced discrete roughness elements (DRE) in a swept wing boundary layer. The time-averaged velocity fields are acquired in a volumetric domain by high-resolution dual-pulse tomographic particle tracking velocimetry. Investigation of...
journal article 2023
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Zoppini, G. (author), Westerbeek, S.H.J. (author), Ragni, D. (author), Kotsonis, M. (author)
The effect of discrete roughness elements on the development and breakdown of stationary crossflow instability on a swept wing is explored. Receptivity to various element heights and chordwise locations is explored using a combination of experimental and theoretical tools. Forcing configurations, determined based on linear stability...
journal article 2022
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Casacuberta Puig, J. (author), Hickel, S. (author), Westerbeek, S.H.J. (author), Kotsonis, M. (author)
The interaction between forward-facing steps of several heights and a pre-existing critical stationary crossflow instability of a swept-wing boundary layer is analysed. Direct numerical simulations (DNS) are performed of the incompressible three-dimensional laminar base flow and the stationary distorted flow that arise from the interaction...
journal article 2022
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Rius Vidales, A.F. (author), Kotsonis, M. (author)
Experiments have been conducted on a swept wing model in a low-turbulence wind tunnel at chord Reynolds number of to investigate the unsteady interaction of a forward-facing step (FFS) with incoming stationary crossflow (CF) vortices. The impact of varying the FFS height on the development and growth of primary and secondary CF disturbances...
journal article 2022
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Dash, A. (author), Poelma, C. (author)
We revisit the laminar–turbulent transition of a fine-grained slurry in a large pipe. The combination of long measurement times in an industrial-scale facility and ultrasound imaging allows us to observe and address anomalous trends. Under turbulent conditions, the flow is homogeneous and steady. However, under laminar conditions, two types of...
journal article 2022
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Rius Vidales, A.F. (author), Kotsonis, M. (author)
The impact of a forward-facing step (FFS) on the development of stationary crossflow instability is investigated on a swept wing model in a low-turbulence wind tunnel at chord Reynolds number of. Infrared thermography and particle image velocimetry measurements are used to quantify the transition location and growth of the crossflow...
journal article 2021
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Zammert, S. (author), Eckhardt, B.E. (author)
Plane Poiseuille flow, the pressure-driven flow between parallel plates, shows a route to turbulence connected with a linear instability to Tollmien-Schlichting (TS) waves, and another route, the bypass transition, that can be triggered with finite-amplitude perturbation. We use direct numerical simulations to explore the arrangement of the...
journal article 2019
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Kurelek, J.W. (author), Kotsonis, M. (author), Yarusevych, S. (author)
Transition and flow development in a separation bubble formed on an airfoil are studied experimentally. The effects of tonal and broadband acoustic excitation are considered since such acoustic emissions commonly result from airfoil self-noise and can influence flow development via a feedback loop. This interdependence is decoupled, and the...
journal article 2018
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Ye, Q. (author), Schrijer, F.F.J. (author), Scarano, F. (author)
The variation of transitional flow features past a micro-ramp is investigated when the Reynolds number is decreased approaching the critical regime. Experiments are conducted in the incompressible flow spanning from supercritical to subcritical roughness-height-based Reynolds number ( , 730, 460 and 320) with tomographic particle image...
journal article 2018
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Pausch, M. (author), Eckhardt, B.E. (author)
The transition to turbulence in flows where the laminar profile is linearly stable requires perturbations of finite amplitude. “Optimal” perturbations are distinguished as extrema of certain functionals, and different functionals give different optima. We here discuss the phase space structure of a 2D simplified model of the transition to...
journal article 2015
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