The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Max D Gunzburger - One of the best experts on this subject based on the ideXlab platform.
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Boundary Velocity control of incompressible flow with an application to viscous drag reduction
Siam Journal on Control and Optimization, 1992Co-Authors: Max D Gunzburger, Thomas P SvobodnyAbstract:An optimal Boundary control problem for the Navier–Stokes equations is presented. The control is the Velocity on the Boundary, which is constrained to lie in a closed, convex subset of $H^{{1 / 2}} $ of the Boundary. A necessary condition for optimality is derived. Computations are done when the control set is actually finite-dimensional, resulting in an application to viscous drag reduction.
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Optimal Boundary control of nonsteady incompressible flow with an application to viscous drag reduction
29th IEEE Conference on Decision and Control, 1990Co-Authors: Thomas P Svobodny, Max D GunzburgerAbstract:The objective of this study is to characterize the Boundary Velocity distribution that in some sense gives the lowest viscous drag for viscous, incompressible flows. The case is considered where the control is explicitly constrained. Necessary conditions are presented for optimal controls for the Navier-Stokes equations in a bounded region. An application to reducing viscous drag by blowing and suction is discussed. The first part of the study considers static control; the second part is concerned with time-varying optimal controls.
Thomas P Svobodny - One of the best experts on this subject based on the ideXlab platform.
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Boundary Velocity control of incompressible flow with an application to viscous drag reduction
Siam Journal on Control and Optimization, 1992Co-Authors: Max D Gunzburger, Thomas P SvobodnyAbstract:An optimal Boundary control problem for the Navier–Stokes equations is presented. The control is the Velocity on the Boundary, which is constrained to lie in a closed, convex subset of $H^{{1 / 2}} $ of the Boundary. A necessary condition for optimality is derived. Computations are done when the control set is actually finite-dimensional, resulting in an application to viscous drag reduction.
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Optimal Boundary control of nonsteady incompressible flow with an application to viscous drag reduction
29th IEEE Conference on Decision and Control, 1990Co-Authors: Thomas P Svobodny, Max D GunzburgerAbstract:The objective of this study is to characterize the Boundary Velocity distribution that in some sense gives the lowest viscous drag for viscous, incompressible flows. The case is considered where the control is explicitly constrained. Necessary conditions are presented for optimal controls for the Navier-Stokes equations in a bounded region. An application to reducing viscous drag by blowing and suction is discussed. The first part of the study considers static control; the second part is concerned with time-varying optimal controls.
Robert A Canfield - One of the best experts on this subject based on the ideXlab platform.
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Boundary Velocity method for continuum shape sensitivity of nonlinear fluid structure interaction problems
Journal of Fluids and Structures, 2013Co-Authors: Robert A CanfieldAbstract:Abstract A Continuum Sensitivity Equation (CSE) method was developed in local derivative form for fluid–structure shape design problems. The Boundary Velocity method was used to derive the continuum sensitivity equations and sensitivity Boundary conditions in local derivative form for a built-up joined beam structure under transient aerodynamic loads. For nonlinear problems, when the Newton–Raphson method is used, the tangent stiffness matrix yields the desired sensitivity coefficient matrix for solving the linear sensitivity equations in the Galerkin finite element formulation. For built-up structures with strain discontinuity, the local sensitivity variables are not continuous at the joints, requiring special treatment to assemble the elemental local sensitivities and the generalized force vector. The coupled fluid–structure physics and continuum sensitivity equations for gust response of a nonlinear joined beam with an airfoil model were posed and solved. The results were compared to the results obtained by finite difference (FD) method.
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Boundary Velocity method for continuum shape sensitivity of nonlinear fluid–structure interaction problems
Journal of Fluids and Structures, 2013Co-Authors: Robert A CanfieldAbstract:Abstract A Continuum Sensitivity Equation (CSE) method was developed in local derivative form for fluid–structure shape design problems. The Boundary Velocity method was used to derive the continuum sensitivity equations and sensitivity Boundary conditions in local derivative form for a built-up joined beam structure under transient aerodynamic loads. For nonlinear problems, when the Newton–Raphson method is used, the tangent stiffness matrix yields the desired sensitivity coefficient matrix for solving the linear sensitivity equations in the Galerkin finite element formulation. For built-up structures with strain discontinuity, the local sensitivity variables are not continuous at the joints, requiring special treatment to assemble the elemental local sensitivities and the generalized force vector. The coupled fluid–structure physics and continuum sensitivity equations for gust response of a nonlinear joined beam with an airfoil model were posed and solved. The results were compared to the results obtained by finite difference (FD) method.
Cheng-zhong Xu - One of the best experts on this subject based on the ideXlab platform.
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On the spectrum-determined growth condition of a vibration cable with a tip mass
IEEE Transactions on Automatic Control, 2000Co-Authors: Cheng-zhong XuAbstract:We show that the spectrum-determined growth condition holds for the closed-loop system of a vibration cable with a tip mass and linear Boundary feedback control. The optimal decay rate of the energy for a case left unsolved previously is determined, and the asymptotic expansion of the associated semigroup is obtained. As a consequence of the approach, we show, in a different point of view, the lack of uniform exponential stability of the system with only Boundary Velocity feedback control.
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Boundary Velocity feedback stabilization of a vibrating equation with a variable coefficient
Proceedings of the 37th IEEE Conference on Decision and Control (Cat. No.98CH36171), 1998Co-Authors: B. Chentouf, Cheng-zhong Xu, G. SalletAbstract:This paper deals with Boundary stabilization of a vibrating equation with a variable coefficient. We propose a stabilizing nonlinear Boundary feedback law which only depends on Boundary velocities. Uniform decay rate and rational decay rate of the associated energy are also estimated in terms of growth conditions on the feedback functions.
G. Sallet - One of the best experts on this subject based on the ideXlab platform.
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Boundary Velocity feedback stabilization of a vibrating equation with a variable coefficient
Proceedings of the 37th IEEE Conference on Decision and Control (Cat. No.98CH36171), 1998Co-Authors: B. Chentouf, Cheng-zhong Xu, G. SalletAbstract:This paper deals with Boundary stabilization of a vibrating equation with a variable coefficient. We propose a stabilizing nonlinear Boundary feedback law which only depends on Boundary velocities. Uniform decay rate and rational decay rate of the associated energy are also estimated in terms of growth conditions on the feedback functions.