Journal ArticleDOI
Boundary-layer receptivity to freestream disturbances
TLDR
The boundary-layer receptivity to external acoustic and vortical disturbances is reviewed in this article. But, the authors do not consider the effects of external acoustic or vortic disturbances on the boundary layer.Abstract:
The current understanding of boundary-layer receptivity to external acoustic and vortical disturbances is reviewed. Recent advances in theoretical modeling, numerical simulations, and experiments are discussed. It is shown that aspects of the theory have been validated and that the mechanisms by which freestream disturbances provide the initial conditions for unstable waves are better understood. Challenges remain, however, particularly with respect to freestream turbulenceread more
Citations
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Journal ArticleDOI
Experimental Study of a Boundary Layer on a Heated Flat Plate
Pavel Antoš,Sergei Kuznetsov +1 more
TL;DR: In this paper, a probe with parallel wires was used for velocity-temperature measurement in a closed-circuit wind tunnel with several levels of heat flux at the wall, and the wall temperature was set up in the interval from 20 oC to 200 oC.
Book ChapterDOI
Thresholds of nature: How understanding one of nature's penultimate laws led to the PowerCone, a biomimetic energy source
TL;DR: In this article , the authors explore various aerodynamic mechanisms and strategies of the falling maple key and describe how they were applied to the design of wind and tidal turbines, revealing the cross-disciplinary nature of biomimetic designs, and the underlying role of threshold theory and principles of time-dependent energy transfer in nature's strategies.
Journal Article
In-Flight Active Wave Cancelation with Delayed-x-LMS Control Algorithm in a Laminar Boundary Layer
Bernhard Simon,Nicolò Fabbiane,Timotheus Nemitz,Shervin Bagheri,Dan S. Henningson,Sven Grundmann +5 more
TL;DR: This manuscript demonstrates the first successful application of the delayed-x-LMS (dxLMS) control algorithm for TS-wave cancelation, which is operated without a model and is able to adapt to varying conditions that may occur during flight in atmosphere.
Journal ArticleDOI
A Technique to Control the Decay of Freestream Turbulence for Transitional Flow Simulations
TL;DR: In this paper , the authors proposed a new approach to control the decay of freestream turbulence that avoids setting high values for the inlet eddy viscosity by modifying the dissipation term of the turbulence model only in the free-stream.
References
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Book
Stability and Transition in Shear Flows
TL;DR: In this article, the authors present an approach to the Viscous Initial Value Problem with the objective of finding the optimal growth rate and the optimal response to the initial value problem.
Journal ArticleDOI
A note on an algebraic instability of inviscid parallel shear flows
TL;DR: In this paper, it was shown that all parallel inviscid shear flows of constant density are unstable to a wide class of initial infinitesimal three-dimensional disturbances in the sense that, according to linear theory, the kinetic energy of the disturbance will grow at least as fast as linearly in time.
Journal ArticleDOI
Parabolized stability equations
TL;DR: Parabolized stability equations (PSE) have been used for aerodynamic design of laminar flow control systems as discussed by the authors, and they can be obtained at modest computational expense.
Journal ArticleDOI
Optimal disturbances and bypass transition in boundary layers
TL;DR: In this article, the authors used the steady boundary-layer approximation to calculate the upstream disturbances experiencing maximum spatial energy growth, which are numerically calculated using techniques commonly employed when solving optimal-control problems for distributed parameter systems.
Journal ArticleDOI
Reynolds number independent instability of the boundary layer over a flat surface : optimal perturbations
TL;DR: In this article, the dependence on initial conditions of the three-dimensional algebraic spatial instability of the Blasius boundary layer is examined by a recently developed method of receptivity analysis based on the upstream integration of adjoint equations.