Stanley Corrsin Award Talk: Turbulence Structure and Modeling in the Frequency Domain

The frequency domain, long used to characterize linear amplification of disturbances in transitional flows, is increasingly being used to study stationary turbulence and coherence structures via resolvent analysis. In the turbulent case, the frequency domain has proven useful for characterizing the statistics of coherent structures and the mechanisms by which they arise. Such analyses are buoyed by the close relationship between resolvent modes and structures educed using the spectral proper orthogonal decomposition (SPOD), allowing detailed validations with experimental and simulation data, on the one hand, and data-driven calibrations and optimizations of models, on the other. In this talk I will highlight a number of applications to both boundary layers and jets and discuss some promising avenues for the development of reduced-order models of coherent structures. I will also discuss the frequency-domain techniques in the context of the current computational landscape, identify bottlenecks, and speculate about the future of these techniques.