Receptivity of swept-wing transition to surface roughness
G. (Giulia) Zoppini
Doctoral Candidate
Dr. M. (Marios) Kotsonis
Associate Professor
Dr. D. (Dani) Ragni
Associate Professor
Nowadays, the majority of transport aircrafts are equipped with swept wings on which the main mechanism responsible for boundary layer transition is the generation, growth and breakdown of crossflow instabilities (CFI). Crossflow is a secondary flow that develops in the boundary layer perpendicularly to the direction of the inviscid streamline and origins flow instabilities in the form of stationary or travelling (co-rotating) vortices. Their development and intensity are linked to two main external factors: the turbulence level of the freestream flow and the surface roughness, particularly important in the vicinity of the leading edge. The mechanism that leads to the entrainment of these external disturbances in the boundary layer is called receptivity and is one of the main aspects of crossflow instability that this research wants to investigate with the objective of gaining deeper understanding of the physical phenomena dominating it. Experiments will be carried out applying a combination of the classical measurement techniques, as infrared thermography, hotwire anemometry and PIV to obtain a full spatio-temporal description of the flow. Such result can only be achieved through high spatial accuracy measures and excellent wind tunnel flow quality, and can eventually lead to a complete and objective characterization of the dominant flow mechanisms.
Zoppini, G., Ragni, D., & Kotsonis, M. (2022). Experimental Investigation of Isolated Roughness Induced Transition in a Swept Wing Boundary Layer. In AIAA SCITECH 2022 Forum [AIAA 2022-1213] (AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022).
Zoppini, G., Westerbeek, S., Ragni, D., & Kotsonis, M. (2022). Receptivity of crossflow instability to discrete roughness amplitude and location. Journal of Fluid Mechanics, 939, [A33].
Zoppini, G., Ragni, D., & Kotsonis, M. (2022). Transition due to isolated roughness in a swept wing boundary layer. Physics of Fluids, 34(8), [084113].
Zoppini, G., Ragni, D., & Kotsonis, M. (2021). Experimental Investigation on Receptivity of Crossflow Instability to Discrete Roughness Amplitude and Location. In AIAA Scitech 2021 Forum: 11–15 & 19–21 January 2021, Virtual Event [AIAA 2021-0152] American Institute of Aeronautics and Astronautics Inc. (AIAA).
Mario
Daniele Ragni graduated in Thermo-Mechanical Engineering at the Polytechnic University of Marche (2007). Obtained the Ph.D. in 2012 (Faculty of Aerospace Engineering TU Delft) and joined TU Delft at the section of Wind Energy in the AWEP Department in the same year.
