2019 **Abstract:** The current work presents a realizable method to control streaky disturbances in boundary layer flows and delay transition to turbulence by means of active flow control. Numerical simulations of the nonlinear transitional regime in a Blasius boundary layer are performed where streaks are excited in the boundary layer by means of a high level of free-stream turbulence. The occurring disturbances are measured by means of localized wall-shear-stress sensors and damped out using near-wall actuators, which resemble…

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(33 citation statements)

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“…The linearized Navier-Stokes operator here involves only the molecular viscosity, as in McKeon & Sharma (2010). Even though it has been shown in some works that inclusion of an eddy viscosity improves the agreement between resolvent modes and flow statistics (Morra et al 2019;Pickering et al 2020), the present choice is motivated by a more straightforward interpretation of the forcing f as the nonlinear terms; more detailed analysis of such forcing terms are currently being carried out by our group in related works (Nogueira et al 2020). All variables here are Fourier transformed in time, streamwise and azimuthal directions.…”

confidence: 99%

“…The linearized Navier-Stokes operator here involves only the molecular viscosity, as in McKeon & Sharma (2010). Even though it has been shown in some works that inclusion of an eddy viscosity improves the agreement between resolvent modes and flow statistics (Morra et al 2019;Pickering et al 2020), the present choice is motivated by a more straightforward interpretation of the forcing f as the nonlinear terms; more detailed analysis of such forcing terms are currently being carried out by our group in related works (Nogueira et al 2020). All variables here are Fourier transformed in time, streamwise and azimuthal directions.…”

confidence: 99%

“…where N β is the number of discrete transverse wavenumbers considered, provides empirically identified impulse responses which may be directly applied in the ERA method for the construction of ROMs for designing LQG. This procedure based only on the measured signal, which permits the definition of LQG controllers even for experimental implementations, was firstly introduced in Morra et al (2019) and the reader is directed for such work for further details. Application of ERA for this problem results in a system with N ERA = 387 modes, which accurately reproduces the empirically identified transfer functions.…”

confidence: 99%

“…Figure 2 presents a sample of the prediction of z(t, x 3 ) from the measurements y(t, x 3 ) for the set-up considered in this paper, and validates the procedure. For more details concerning the application of the proposed methodology for the time-domain prediction of streaky structures induced by free-stream turbulence, the reader is referred to the work of Morra et al (2019), which firstly introduced the method for this type of application.…”

confidence: 99%