Controllability of 3D incompressible Euler equations by a finite-dimensional external force

In this paper, we study the control system associated with the incompressible 3D Euler system. We show that the velocity field and pressure of the fluid are exactly controllable in projections by the same finite-dimensional control. Moreover, the velocity is approximately controllable. We also prove that 3D Euler system is not exactly controllable by a finite-dimensional external force

Generation of two-dimensional water waves by moving bottom disturbances

We investigate the potential and limitations of the wave generation by disturbances moving at the bottom. More precisely, we assume that the wavemaker is composed of an underwater object of a given shape which can be displaced according to a prescribed trajectory. We address the practical question of computing the wavemaker shape and trajectory generating a wave with prescribed characteristics. For the sake of simplicity we model the hydrodynamics by a generalized forced Benjamin-Bona-Mahony (BBM) equation. This practical problem is reformulated as a constrained nonlinear optimization problem. Additional constraints are imposed in order to fulfill various practical design requirements. Finally, we present some numerical results in order to demonstrate the feasibility and performance of the proposed methodology.Comment: 21 pages, 7 figures, 1 table, 69 references. Other author's papers can be downloaded at http://www.denys-dutykh.com

Global exact controllability in infinite time of Schr\"odinger equation: multidimensional case

We prove that the multidimensional Schr\"odinger equation is exactly controllable in infinite time near any point which is a finite linear combination of eigenfunctions of the Schr\"odinger operator. We prove that, generically with respect to the potential, the linearized system is controllable in infinite time. Applying the inverse mapping theorem, we prove the controllability of the nonlinear system

ZnO nanopowder derived from brass ash: Sintering behavior and mechanical properties

The present investigation studied the recycling of zinc from brass ash which is a secondary product produced during the brass smelting process. A retiring cycle was devised to produce high-purity ZnO nanopowders. Recovery of > 90 wt% of the total zinc available was achieved after the calcination of brass ash at 700 °C and a multistage hydrometallurgical treatment at room temperature. ZnO powder produced by the developed method was analyzed by X-ray diffraction, transmission electron scanning microscopy, ICP-AES and BET analysis. The ZnO nanopowder obtained from the brass ash was well dispersed and the size of the individual particles was in the range of 30–50 nm. The purity of the powder was 99.83 wt%, and the surface area was about 30.5 m2/g. A relative density level of about 98.1% was reached with ZnO pellets sintered at 1300 °C

Controllability and stabilization of the incompressible and compressible Euler equations

Dans cette thèse, on étudie la contrôlabilité et la stabilisation de certaines équations aux dérivées partielles . On s'intéresse d'abord au problème du contrôle de l'équation d'Euler 3D incompressible par une force extérieure de dimension finie. Nous montrons que pour un choix approprié de l'espace de contrôle, la vitesse et la pression du fluide sont exactement contrôlables en projections. De plus, la vitesse est approximativement contrôlable. Nous montrons aussi que le système en question n'est pas exactement contrôlable par une force extérieure de dimension finie.On étudie aussi la contrôlabilité de l'équation d'Euler 3D compressible. Le contrôle est une force extérieure de dimension finie agissant uniquement sur l'équation de la vitesse. Nous montrons que la vitesse et la densité du fluide sont simultanément contrôlables. En particulier, le système est approximativement contrôlable et exactement contrôlable en projections. Dans la dernière partie, on étudie la stabilisation de l'équation d'Euler dans un cylindre infini.Nous montrons que pour toute solution stationnaire (c,0) du système d'Euler il existe un contrôle supporté dans une partie de la frontière du cylindre qui stabilise le système à (c,0).In this thesis, we study the controllability and stabilization of certain partial differential equations.We consider first the problem of control of the 3D incompressible Euler equationby an external force of finite dimension. We show that for an appropriate choice of control space, the velocity and the pressure of the fluid are exactly controllable in projections.Moreover, the velocity is approximately controllable. We also show that the system in question is not exactly controllable by a finite-dimensional external force.We also study the controllability of the 3D compressible Euler equation. The control is a finite-dimensional external force acting only on the velocity equation. We show that the velocity and density of the fluid are simultaneously controllable. In particular, the system is approximately controllable and exactly controllable in projections.The last section of the thesis is devoted to the study of a stabilization problem for the 2D incompressible Euler system in an infinite strip with boundary controls. We show that for any stationary solution (c,0) of the Euler system there is a control which is supported in a given bounded part of the boundary of the strip and stabilizes the system to (c,0)

Global exact controllability in infinite time of Schrödinger equation

In this paper, we study the problem of controllability of Schrödinger equation. We prove that the system is exactly controllable in infinite time to any position. The proof is based on an inverse mapping theorem for multivalued functions. We show also that the system is not exactly controllable in finite time in lower Sobolev spaces