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Record 1 of 36328
Extension of a nonlinear systems theory to general-frequency unsteady transonic aerodynamic responses
Author and Affiliation:
Silva, Walter A.(NASA Langley Research Center, Hampton, VA, United States)
Abstract: A methodology for modeling nonlinear unsteady aerodynamic responses, for subsequent use in aeroservoelastic analysis and design, using the Volterra-Wiener theory of nonlinear systems is presented. The methodology is extended to predict nonlinear unsteady aerodynamic responses of arbitrary frequency. The Volterra-Wiener theory uses multidimensional convolution integrals to predict the response of nonlinear systems to arbitrary inputs. The CAP-TSD (Computational Aeroelasticity Program - Transonic Small Disturbance) code is used to generate linear and nonlinear unit impulse responses that correspond to each of the integrals for a rectangular wing with a NACA 0012 section with pitch and plunge degrees of freedom. The computed kernels then are used to predict linear and nonlinear unsteady aerodynamic responses via convolution and compared to responses obtained using the CAP-TSD code directly. The results indicate that the approach can be used to predict linear unsteady aerodynamic responses exactly for any input amplitude or frequency at a significant cost savings. Convolution of the nonlinear terms results in nonlinear unsteady aerodynamic responses that compare reasonably well with those computed using the CAP-TSD code directly but at significant computational cost savings.
Publication Date: Jan 01, 1993
Document ID:
19930050125
(Acquired Dec 28, 1995)
Accession Number: 93A34122
Subject Category: AERODYNAMICS
Report/Patent Number: AIAA PAPER 93-1590
Document Type: Conference Paper
Publication Information: In: AIAA(ASME)ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 34th and AIAA/ASME Adaptive Structures Forum, La Jolla, CA, Apr. 19-22, 1993, Technical Papers. Pt. 5 (A93-33876 1; p. 2490-2503.; (SEE A93-33876)
Publisher Information: American Institute of Aeronautics and Astronautics, Washington, United States
Financial Sponsor: NASA; United States
Organization Source: NASA Langley Research Center; Hampton, VA, United States
Description: 14p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: AEROELASTICITY; NONLINEAR SYSTEMS; RECTANGULAR WINGS; SERVOCONTROL; UNSTEADY AERODYNAMICS; VOLTERRA EQUATIONS; AEROSERVOELASTICITY; COMPUTATIONAL FLUID DYNAMICS; DEGREES OF FREEDOM; FAST FOURIER TRANSFORMATIONS
Imprint And Other Notes: In: AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 34th and AIAA/ASME Adaptive Structures Forum, La Jolla, CA, Apr. 19-22, 1993, Technical Papers. Pt. 5 (A93-33876 13-39), p. 2490-2503.
Availability Source: Other Sources
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