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A simulation based approach for nonlinear dynamical modelling and feedback control of the drag to lift ratio for aerofoils is investigated through case studies involving NACA 23012, ag13 and b737a aerofoils. The flow around the aerofoils is studied via numerical solutions of the 2D Navier–Stokes (NS) equations. A standard computational fluid dynamics (CFD) solver is extended to be able to measure...
In this paper we investigate the control of flow problems where the control objective is to reduce the oscillation amplitude while keeping the frequency of oscillation between predefined limits at all times. Starting from a simple model representing the oscillatory mode dynamics of the governing equations, the conditions that the control parameters must satisfy in order to achieve the desired objective...
In this paper a novel method is proposed for constructing linear parameter varying (LPV) system models through adaptation. For a class of nonlinear systems, an LPV model is built using its linear part, and its coefficients are considered as time-varying parameters. The variation in time is controlled by an adaptation scheme with the goal of keeping the trajectories of the LPV system close to those...
In this paper, we utilize wavelet transform to obtain dynamical models describing the behavior of fluid flow in a local spatial region of interest. First, snapshots of the flow are obtained from experiments or from computational fluid dynamics (CFD) simulations of the governing equations. A wavelet family and decomposition level is selected by assessing the reconstruction success under the resulting...
In this paper we study various computationally intelligent architectures for prediction of pressure values and velocity components of flow past a three-element airfoil. Six sensor locations are selected around the airfoil and the goal is to predict the flow behavior at the rear of the airfoil using pressure readings from the remaining five sensors. To make the problem more interesting we require the...
Representation of knowledge within a neural model is an active field of research involved with the development of alternative structures, training algorithms, learning modes and applications. Radial Basis Function Neural Networks (RBFNNs) constitute an important part of the neural networks research as the operating principle is to discover and exploit similarities between an input vector and a feature...
Two control input separation methods for control-oriented reduced-order modeling of flow systems are developed and implemented in a cavity flow experimental facility. The proposed methods are 1) actuated POD expansion with stochastic estimation and 2) optimization on a Hilbert space, respectively. These methods extend the baseline flow model through the use of innovation vectors, which capture the...
In this paper, nonlinear control systems whose dynamics are quadratic with respect to state, and bilinear with respect to state and input, which exhibit an oscillation caused by a stable limit cycle for zero input are studied. The effect of linear control on this model is analyzed using modal forms and center manifold theory. It is found that the oscillation amplitude depends both on terms linear...
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