Global Nonlinear Parametric Modeling Using Multivariate13; Orthogonal Functions - Application to F-16 Aerodynamics

Ismail, Shaik and Singh, Jatinder (2004) Global Nonlinear Parametric Modeling Using Multivariate13; Orthogonal Functions - Application to F-16 Aerodynamics. Technical Report. National Aerospace Laboratories, Bangalore, India.

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    Abstract

    This report discusses a simple technique for identifying global models for nonlinear aerodynamic force and moment coefficients of aircraft, from wind tunnel database, using multivariate orthogonal functions. The aerodynamic coefficients are first expressed as truncated series of ordinary polynomial functions. The ordinary polynomial functions are then orthogonalized using the Gram-Schmidt procedure. The orthogonal functions that are to be included in the global are chosen on the basis of Predicted Squared Error, which is a sum of the conventional Mean Squared Error and a Over-Fit Penalty. In the present investigation, software was developed in MATLAB and used to identify the global models for F-16 aerodynamic force and moment coefficients from a simplified subsonic (Mach lt; 0.6) wind tunnel database available in open literature. The identified global models agree with those found in literature for the same wind tunnel database, but using a more complex mathematical method for the generation of orthogonal functions. This report gives a detailed account of the results obtained from identification of F-16 global models.

    Item Type: Proj.Doc/Technical Report (Technical Report)
    Uncontrolled Keywords: Global model;Response surface fitting;Multivariate orthogonal functions;F-16 subsonic wind tunnel database;Predicted squared error;Over-fit penalty
    Subjects: MATHEMATICAL AND COMPUTER SCIENCES > Mathematical and Computer Scienes(General)
    Division/Department: Flight Mechanics and Control Division, Flight Mechanics and Control Division
    Depositing User: Smt Bhagya Rekha KA
    Date Deposited: 03 Feb 2009
    Last Modified: 24 May 2010 09:41
    URI: http://nal-ir.nal.res.in/id/eprint/1264

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