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2 results on '"Adjoint optimal control"'

1. Computations of optimal cylinder flow control in weakly conductive fluids

Author

Zhang, Hui, Fan, Bao-chun, and Chen, Zhi-hua

Subjects
*COMPUTATIONAL fluid dynamics, *FLUID mechanics, *CONTROL theory (Engineering), *THERMAL conductivity, *ENGINE cylinder hydrodynamics, *ELECTROMAGNETISM, *LORENTZ force, *NAVIER-Stokes equations
Abstract

Abstract: A nonlinear adjoint-based optimal control approach of cylinder wake by electromagnetic force has been investigated numerically in the paper. A cost functional representing the balance of the regulated quantities with different weights and interaction parameter N (Lorentz force) has been constituted, where the regulated quantities related with flow and force are taken as targets of regulation and the Lorentz force, (as interaction parameter N), is taken as a control input. Based on the cost functional and Navier–Stokes equations, the corresponding adjoint equations have been derived and the sensitivity of the cost functional is found to be a simple function of the adjoint stream function in the adjoint field. For the different regulations, the forms of optimal control rules are similar while the adjoint equations are different. The receding-horizon predictive control setting is employed to discuss the optimal control problems. Under the action of optimal N(t), the flow separation is suppressed fully, so that the oscillations of drag and lift are suppressed and the total drag coefficient decreases dramatically. For the different regulations, the control effects have some differences due to the different values of optimal inputs corresponding to the different adjoint flow fields. [Copyright &y& Elsevier]

Published
2010
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2. Adjoint optimal control problems for fluid-structure interaction systems

Author

Sandro Manservisi, D. Cerroni, L. Zaniboni, F. Menghini, R. Davià, ECCOMAS, Cerroni, D., Davià, R., Manservisi, S., Menghini, F, and Zaniboni, L.

Subjects
Physics::Fluid Dynamics, Mathematical optimization, Adjoint equation, Artificial Intelligence, Adjoint optimal control, Applied Mathematics, Fluid–structure interaction, Fluid-structure interaction, Optimal control, Mathematics, ComputingMethodologies_COMPUTERGRAPHICS
Abstract

In the last years adjoint optimal control has been increasingly used for design and simulations in several research fields. Applications to Computational Fluid Dynamics problems dedicated to the study of transient-diffusion equations, shape optimization problems, fluid-solid conjugate heat transfer and turbulent flows can be found in literature. The study of Fluid-Structure Interaction problems gained popularity recently because of many interesting applications in engineering and biomedical fields. In this paper we study adjoint optimal control problems for Fluid-Structure Interaction systems in order to improve the advantages of using FSI simulations when designing engineering devices where fluid-dynamical interactions between a fluid and a solid play a significant role. We assess distributed optimal control problems with the purpose to control the fluid behavior by moving the solid region to obtain a desired fluid velocity in specific parts of the domain. The adjoint equations of the FSI monolithic system are derived and the optimality system solved for some simple cases with an in-house finite element code with mesh-moving capabilities for the study of large displacements in the solid. The approach presented in this work is general and can be used to assess different objectives and types of control in future works.

Published
2016

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