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
Feedback control of slowly-varying transient growth by an array of plasma actuators
TL;DR: In this paper, a closed-loop feedback control of boundary layer streaks embedded in a laminar boundary layer and experiencing transient growth is investigated, which is inherent to bypass boundary layer transition.
Receptivity of a boundary-layer flow to a three-dimensional hump at finite Reynolds numbers
Anatoli Tumin,Eli Reshotko +1 more
TL;DR: In this paper, the receptivity of boundary-layer flow to a three-dimensional hump (an array of humps) at a finite Reynolds number is solved with the help of an expansion of the linearized solution of Navier-Stokes equations into the biorthogonal eigenfunction system.
Proceedings ArticleDOI
In-Flight Receptivity Experiments on a 30-Degree Swept- Wing using Micron-Sized Discrete Roughness Elements
TL;DR: In this article, the leading edge of a Cessna O-2A aircraft with a 30-degree swept-wing was used to measure disturbance wall shear stress and the roughness height was varied from 0 to 50 microns both in the positive and negative sense.
Posted Content
Adaptive and model-based control theory applied to convectively unstable flows
TL;DR: In this article, a review of active control for the delay of laminar-turbulent transition in boundary layers has been made a significant progress in the last two decades, but the employed strategies have been many and dispersed.
Journal ArticleDOI
A local scattering theory for the effects of isolated roughness on boundary-layer instability and transition: transmission coefficient as an eigenvalue
Xuesong Wu,Ming Dong +1 more
TL;DR: In this article, the impact of abrupt changes (such as isolated roughness, gaps and local suctions) on boundary-layer transition is investigated. But the authors focus on the effect of roughness on boundary layer transition.
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.