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Showing 1 to 20 of 74 for “"Proper Orthogonal Decomposition (POD)"”.
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Incremental proper orthogonal decomposition for PDE simulation data: Algorithms and analysis
… propose an incremental algorithm to compute the proper orthogonal decomposition (POD) of simulation data for a partial differential equation. Specifically, we modify an incremental matrix SVD algorithm of Brand to accommodate data arising from Galerkin-type simulation methods for time dependent …
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Approximate Deconvolution Reduced Order Modeling
… realistic flows. In this LES-ROM framework, the proper orthogonal decomposition (POD) is used to define the ROM basis and a POD differential filter is used to define the large ROM structures. An approximate deconvolution (AD) approach is used to solve the ROM closure problem and develop a new …
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Sensitivity Enhanced Model Reduction
… model in order to increase the accuracy of a proper orthogonal decomposition (POD) basis across a wider range of parameters. Various techniques based on polynomial interpolation and basis alteration are compared. These techniques are performed on a 1-dimensional reaction-diffusion equation and …
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Hydroxyl-Radical Planar Laser-Induced Fluorescence Imaging of Turbulent Supersonic Combustion
… Supersonic Combustion Facility (UVaSCF). Proper orthogonal decomposition (POD) and autocorrelations are performed on the OH PLIF data to extract quantitative information about turbulent fluctuations and length scale correlations. Changes in integral length scales and turbulent energy flow …
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LAMINAR TURBULENT TRANSITION - SPECTRAL ANALYSIS AND COHERENT STRUCTURES OF DNS WAVEPACKETS
… the flow. These are compared with the results of proper orthogonal decomposition (POD). A hybrid POD-FFT approach is also pioneered to synergize the strengths of both methods, taking advantage of the optimal basis constructed by POD, and connecting it with classical theories of Craik and Herbert …
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Computational Simulation of Detonation Waves and Model Reduction for Reacting Flows
… reduction approach based on Galerkin projection, proper orthogonal decomposition (POD) and the discrete empirical interpolation method (DEIM) that addresses the computational challenges involved in the numerical simulations of reacting flows is also proposed and demonstrated.
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Low Order Representations in the Turbulent Wake of a Normal Flat Plate
… expansion using the energetically-optimal proper orthogonal decomposition (POD). The harmonic and shift modes of the LOM are coupled via the mean-field paraboloid in phase space, enabling the construction of a generalized phase-average (GPA). The GPA is shown to capture key flow behaviour …
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Parameter Dependent Model Reduction for Complex Fluid Flows
… model is built using a basis obtained through proper orthogonal decomposition (POD) and Galerkin projection of the system dynamics. In this thesis we present theoretical and numerical results for parameter dependent model reduction techniques. The methods are motivated by the need for surrogate …
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Model Reduction of the Coupled Burgers Equation in Conservation Form
… examine the feasibility and efficiency of the Proper Orthogonal Decomposition (POD) for the coupled Burgers equation. Using POD, we reduce the system to a "minimal" number of ODE's and conduct numerous numerical studies comparing the POD and GFE method. Further numerical experiments consider an …
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Efficient reduced-basis approximation of scalar nonlinear time-dependent convection-diffusion problems, and extension to compressible flow problems
… partial differential equations (PDEs). A proper orthogonal decomposition (POD) procedure is used for the construction of reduced-basis approximation for the field variables. In the presence of highly nonlinear terms, conventional reduced-basis would be inefficient and no longer superior to …
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Reduced Order Model Study of Burgers' Equation using Proper Orthogonal Decomposition
… over the standard FEM. We also utilize Proper Orthogonal Decomposition (POD) as a model reduction technique and modifications of POD that include Global POD, and the sensitivity based modifications Extrapolated POD and Expanded POD. We then use a single baseline parameter in the …
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Impact of Discretization Techniques on Nonlinear Model Reduction and Analysis of the Structure of the POD Basis
… impact on model reduction techniques, namely Proper Orthogonal Decomposition (POD), Group POD and the Discrete Empirical Interpolation Method (DEIM), is studied. This study is facilitated by examination of several common ODE solvers. Embedded in this process, some results on the structure of …
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Active noise control in supersonic impinging jets using pulsed microjets : actuator design, reduced-order modeling
… proposed using steady microjet injection and the Proper Orthogonal Decomposition (POD) algorithm. The most energetic spatial mode of the unsteady pressure along the nozzle diameter is captured using the POD, which in turn is used to determine the distribution of microjet intensity along the nozzle …
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Proper Orthogonal Decomposition for Reduced Order Control of Partial Differential Equations
… The low order basis is obtained by applying Proper Orthogonal Decomposition (POD) to a set of functional gains, and is referred to as the functional gain POD basis. Low order controllers resulting from the functional gain POD basis are compared with low order controllers resulting from more …
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Model order reduction in the frequency domain via spectral proper orthogonal decomposition
… Specifically, we emphasize the usage of spectral proper orthogonal decomposition (SPOD), recently revived by Towne et. al. (2018), which results in sets of orthogonal modes, each oscillating at a single frequency, that are said to optimally represent coherent-structures evolving in space and time. …
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Turbulent structures in smooth and rough open channel flows: effect of depth
… of the free surface on the turbulent structures. Proper orthogonal decomposition (POD) and swirling strength analysis were employed to investigate the structures present in the flow. Analysis of the POD reconstructed velocity fields reveals the presence of large-scale energetic structures near the …
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CFD Analyses of Flow Structures in Air-Ingress and Rod Bundle Problems
… with the experiments. Wavelet analysis and Proper Orthogonal Decomposition (POD) are used to study the flow behaviors and flow patterns. For the air-ingress phenomenon, Brunt-Vaisala frequency, or buoyancy frequency, predicts a frequency of 2.34 Hz, which is confirmed by the dominant …
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Reduced-Order Modeling and Design Optimization of Thermomechanical Shape Memory Alloy-Based Bistable Microactuators and Hyperelastic Material Systems
… cost, reduced-order modeling techniques based on proper orthogonal decomposition (POD) are introduced. These methods significantly decrease the number of degrees of freedom while maintaining high accuracy. The reduced models show strong agreement with full finite element simulations, achieving …
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Stereoscopic PIV measurements and proper orthogonal decomposition of a supersonic axisymmetric base flow
… into the global organization of the flow, proper orthogonal decomposition (POD) is performed. The energy convergence and the structures found in the eigenmodes are used to gain insight into the organization of the flow that may not be apparent by observation of the mean flow statistics or …
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Efficient Large Scale Transient Heat Conduction Analysis Using A Parallelized Boundary Element Method
A parallel domain decomposition Laplace transform Boundary Element Method, BEM, algorithm for the solution of large-scale transient heat conduction problems will be developed. This is accomplished by building on previous work by the author and including several new additions (most note-worthy is …
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