Aerodynamic database error filtering via high order singular value decomposition

Jarzabek, Artur Andrzej (2016). Aerodynamic database error filtering via high order singular value decomposition. Thesis (Doctoral), E.T.S.I. Aeronáuticos (UPM). https://doi.org/10.20868/UPM.thesis.40982.

Description

Title: Aerodynamic database error filtering via high order singular value decomposition
Author/s:
  • Jarzabek, Artur Andrzej
Contributor/s:
  • Vega de Prada, Jose Manuel
  • Perales Perales, José Manuel
Item Type: Thesis (Doctoral)
Date: 2016
Subjects:
Faculty: E.T.S.I. Aeronáuticos (UPM)
Department: Vehículos Aeroespaciales [hasta 2014]
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

Esta Tesis presenta un nuevo método para filtrar errores en bases de datos multidimensionales. Este método no precisa ninguna información a priori sobre la naturaleza de los errores. En concreto, los errrores no deben ser necesariamente pequeños, ni de distribución aleatoria ni tener media cero. El único requerimiento es que no estén correlados con la información limpia propia de la base de datos. Este nuevo método se basa en una extensión mejorada del método básico de reconstrucción de huecos (capaz de reconstruir la información que falta de una base de datos multidimensional en posiciones conocidas) inventado por Everson y Sirovich (1995). El método de reconstrucción de huecos mejorado ha evolucionado como un método de filtrado de errores de dos pasos: en primer lugar, (a) identifica las posiciones en la base de datos afectadas por los errores y después, (b) reconstruye la información en dichas posiciones tratando la información de éstas como información desconocida. El método resultante filtra errores O(1) de forma eficiente, tanto si son errores aleatorios como sistemáticos e incluso si su distribución en la base de datos está concentrada o esparcida por ella. Primero, se ilustra el funcionamiento delmétodo con una base de datosmodelo bidimensional, que resulta de la dicretización de una función transcendental. Posteriormente, se presentan algunos casos prácticos de aplicación del método a dos bases de datos tridimensionales aerodinámicas que contienen la distribución de presiones sobre un ala a varios ángulos de ataque. Estas bases de datos resultan de modelos numéricos calculados en CFD. ABSTRACT A method is presented to filter errors out in multidimensional databases. The method does not require any a priori information about the nature the errors. In particular, the errors need not to be small, neither random, nor exhibit zero mean. Instead, they are only required to be relatively uncorrelated to the clean information contained in the database. The method is based on an improved extension of a seminal iterative gappy reconstruction method (able to reconstruct lost information at known positions in the database) due to Everson and Sirovich (1995). The improved gappy reconstruction method is evolved as an error filtering method in two steps, since it is adapted to first (a) identify the error locations in the database and then (b) reconstruct the information in these locations by treating the associated data as gappy data. The resultingmethod filters out O(1) errors in an efficient fashion, both when these are random and when they are systematic, and also both when they concentrated and when they are spread along the database. The performance of the method is first illustrated using a two-dimensional toymodel database resulting fromdiscretizing a transcendental function and then tested on two CFD-calculated, three-dimensional aerodynamic databases containing the pressure coefficient on the surface of a wing for varying values of the angle of attack. A more general performance analysis of the method is presented with the intention of quantifying the randomness factor the method admits maintaining a correct performance and secondly, quantifying the size of error the method can detect. Lastly, some improvements of the method are proposed with their respective verification.

More information

Item ID: 40982
DC Identifier: http://oa.upm.es/40982/
OAI Identifier: oai:oa.upm.es:40982
DOI: 10.20868/UPM.thesis.40982
Deposited by: Archivo Digital UPM 2
Deposited on: 10 Jun 2016 06:58
Last Modified: 09 Dec 2016 23:30
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