A Timoshenko beam equation with boundary feedback control is considered. By an abstract result on the Riesz basis generation for the discrete operators in the Hilbert spaces, we show that the closed-loop system is a Riesz system, that is, the sequence of generalized eigenvectors of the closed-loop system forms a Riesz basis in the state Hilbert space. 1. Introduction. The boundary feedback stab...

Abstract. We consider a star-shaped network consisting of a single node with N ≥ 3 connected arcs. The dynamics on each arc is governed by the wave equation. The arcs are coupled at the node and each arc is controlled at the other end. Without assumptions on the lengths of the arcs, we show that if the feedback control is active at all exterior ends, the system velocity vanishes in finite time....

The stability analysis of the linear and nonlinear Korteweg-de Vries equations in presence a saturated feedback actuator is studied. well-posedness derived by using semigroup results, Schauder's Banach fixed point theorems. exponential shown thanks to an observability inequality, which obtained via contradiction compactness arguments. Finally, alternative proof asymptotic equation presented.

We study the exponential stabilization of the linearized Navier-Stokes equations around an unstable stationary solution, by means of a feedback boundary control, in dimension 2 or 3. The feedback law is determined by solving a Linear-Quadratic control problem. We do not assume that the normal component of the control is equal to zero. In that case the state equation, satisfied by the velocity f...

Linear and nonlinear optimal control have been investigated in transitional channel and boundary layer flows. The flow phenomena that we study are governed by the incompressible Navier–Stokes equations and the main aim with the control is to prevent transition from laminar to turbulent flows. A linear model-based feedback control approach, that minimizes an objective function which measures the...

Given a nonstationary trajectory of the Navier–Stokes system, a finitedimensional feedback boundary controller stabilizing locally the system to the given solution is constructed. Moreover the controller is supported in a given open subset of the boundary of the domain containing the fluid and acts normal to the boundary. In a first step a controller is constructed that stabilizes the linear Os...

We show that a non-dissipative feedback that has been shown in the literature to exponentially stabilize an Euler-Bernoulli beam makes a Rayleigh beam and a Timoshenko beam unstable.

Fibre drawing is an important industrial process for synthetic polymers and optical communications. In the manufacture of optical fibres, precise diameter control is critical to waveguide performance, with tolerances in the submicron range that are met through feedback controls on processing conditions. Fluctuations arise from material non-uniformity plague synthetic polymers but not optical si...

In this paper, a numerical study is presented to investigate a boundary-layer instability on the suction side of a NACA0006 airfoil, induced by aerodynamic sound scattered from a trailingedge. By incorporating a linear stability analysis into the direct simulations with a compressible Navier-Stokes code using high-order accurate schemes, the unsteady characteristics are estimated upon resolving...

We study the exponential stabilization of the linearized Navier-Stokes equations around an unstable stationary solution, by means of a feedback boundary control, in dimension 2 or 3. The feedback law is determined by solving a Linear-Quadratic control problem. We do not assume that the normal component of the control is equal to zero. In that case the state equation, satisfied by the velocity f...