AGARD REPORT NO. 626
AGARD REPORT NO. 626

Author: North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development

Publisher:

Published: 1974

Total Pages: 94

ISBN-13:

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An Integral Equation Method for Boundary Interference in a Perforated-wall Wind Tunnel at Transonic Speeds
An Integral Equation Method for Boundary Interference in a Perforated-wall Wind Tunnel at Transonic Speeds

Author: E. M. Kraft

Publisher:

Published: 1976

Total Pages: 84

ISBN-13:

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The wind tunnel boundary interference at transonic speeds on a thin airfoil in a two-dimensional perforated-wall wind tunnel was determined. The interference was found by applying an integral equation method to the nonlinear transonic small disturbance equation including embedded supersonic regions with shock waves. The kernels of the ensuing integral equation were replaced by series approximations, and the integrals were evaluated in closed form. The iterative technique used to calculate the interference from the integral equation method is shown to converge rapidly, and the computing time for the integral equation method is typically an order of magnitude less than present numerical methods. As a special case, the integral equation method for a thin airfoil in free air was also examined. It was found that the introduction of a novel influence function yields, for the first time, a self-contained integral equation for a lifting airfoil. In addition, a systematic study of the classical assumption used to simplify the integral equation shows that the integral method can provide solutions in good agreement with results from the numerical methods.

Fundamentals of Modern Unsteady Aerodynamics
Fundamentals of Modern Unsteady Aerodynamics

Author: Ülgen Gülçat

Publisher: Springer Nature

Published: 2021-01-04

Total Pages: 445

ISBN-13: 3030607771

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This book introduces the concept of unsteady aerodynamics and its underlying principles. The author provides the readers with a comprehensive review of the fundamental physics of free and forced unsteadiness, the terminology and basic equations of aerodynamics ranging from incompressible flow to hypersonics. The book also covers modern topics related to the developments made in recent years, especially in relation to wing flapping for propulsion. The book is written for graduate and senior year undergraduate students in aerodynamics and also serves as a reference for experienced researchers. Each chapter includes ample examples, questions, problems and relevant references. This 3rd edition includes a new chapter about unsteady applications related to the thrust optimization, aerodynamic stability and trim because there has been much progress in unsteady applications of the flapping wing technology. In addition, further material is presented in Appendix for evaluating the stability derivatives so that no derivation of equations is left incomplete but not overdone in the text.