Print Email Facebook Twitter Capturing the flow Title Capturing the flow: Reduced-order modeling using goal-oriented optimization Author Shajahan, T. Contributor Hulshoff, S.J. (mentor) Faculty Aerospace Engineering Department Aerodynamics, Wind Energy & Propulsion Date 2016-12-21 Abstract The use of detailed numerical simulations for practical applications or in the study of complex flow phenomenon is limited by the computational cost. Over the last two decades, reduced order models (ROMs) have become a viable alternative on account of their low computational cost. ROMs capture only the essential dynamics of interest rather than resolving all the quantities in the flow. Several techniques have been proposed recently to construct ROMs based on the Galerkin projection. However, these techniques are limited in their ability to model the flow as they can only represent specific quantities of interest. In the recent past, a goal-oriented reduced order model (GOROM) has been proposed. The GOROM provides the user the ability to define the optimality constraint to model the flow phenomenon of interest. The GOROM is constructed by solving a goal-oriented optimization problem. The GOROM models the flow phenomenon of interest by projecting the governing equations onto a subspace spanned by a set of optimal basis functions. These optimal basis functions are constructed from a secondary set of basis functions by solving the optimization problem. In the previous work, the goal-oriented optimization problem was defined by developing the semi-continuous formulation (SCF). In this work, the SCF is extended to the incompressible Navier-Stokes equations. The GOROM is constructed by solving the optimization problem using the inexact-Newton trust-region algorithm. This is first demonstrated by constructing the GOROM for the Burgers equation. This is followed by the construction of the GOROM for the incompressible Navier-Stokes equation. The application of the GOROM is demonstrated by modeling the flow for a set of 1D problems. Additionally, the scaling of the computational cost of the construction and application of the GOROM has been investigated. Subject goal-orientedvariational multi-scalereduced-order model To reference this document use: http://resolver.tudelft.nl/uuid:b62c723b-6c3b-4ddc-9538-5973b29e997a Part of collection Student theses Document type master thesis Rights (c) 2016 Shajahan, T. Files PDF Thesis_TShajahan.pdf 2.04 MB Close viewer /islandora/object/uuid:b62c723b-6c3b-4ddc-9538-5973b29e997a/datastream/OBJ/view