A Take on Turbulence: Singing into Chaos
Leveraging the idea of coherent structures in turbulent flows, we seek to study the response of this complex system to a known synthetic structure.
We find turbulent flows all around us, and understanding the behavior of such flows is critical to designing faster, cleaner, quieter transport. This has proved quite challenging, as turbulence is a chaotic and non-linear process. One foothold that many researchers have found is that underpinning the seemingly random flow appear wave-like features, so-called coherent structures, which seem energetically and dynamically significant. We can think of these as distinct musical “notes” supporting the otherwise noisiness of turbulence. The novel experimental tool that is dynamic roughness allows us to precisely generate our own synthetic structures, singing our own note into the flow. We use this synthetic signature to study the turbulent flow system and its response to the known input. Such a framework lends itself to modeling efforts and the study of flow control methods in a way that was not previously achievable.
Figure: Phase-averaged velocity fields (mean subtracted) of the flow response to the dynamic roughness forcing. Red contours indicate flow faster than the local mean, blue contours indicate flow slower.
David Huynh, Beverley McKeon
AFOSR FA 9550-16-1-0361