Calculation of Boundary Layers Near the Stagnation Point of an Oscillating Airfoil

Calculation of Boundary Layers Near the Stagnation Point of an Oscillating Airfoil

Author: Tuncer Cebeci

Publisher:

Published: 1983

Total Pages: 22

ISBN-13:

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The results of an investigation of boundary layers close to the stagnation point of an oscillating airfoil are reported. Two procedures for generating initial conditions - the characteristics-box scheme and a quasi-static approach - were investigated, and the quasi-static approach was shown to be appropriate provided the initial region was far from any flow separation. With initial conditions generated in this way, the unsteady boundary-layer equations were solved for the flow in the leading-edge region of a NACA 0012 airfoil oscillating from 0 degrees to 5 degrees. Results were obtained for both laminar and turbulent flow, and, in the latter case, the effect of transition was assessed by specifying its occurrence at different locations. The results demonstrate the validity of the numerical scheme and suggest that the procedures should be applied to calculation of the entire flow around oscillating airfoils. (Author).


Numerical and Physical Aspects of Aerodynamic Flows

Numerical and Physical Aspects of Aerodynamic Flows

Author: T. Cebeci

Publisher: Springer Science & Business Media

Published: 2013-11-09

Total Pages: 618

ISBN-13: 3662126109

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This volume contains revised and edited forms of papers presented at the Symposium on Numerical and Physical Aspects of Aerodynamic Flows, held at the California State University from 19 to 21 January 1981. The Symposium was organized to bring together leading research workers in those aspects of aerodynamic flows represented by the five parts and to fulfill the following purposes : first, to allow the presentation of technical papers which provide a basis for research workers to assess the present status of the subject and to formulate priorities for the future; and second, to promote informal discussion and thereby to assist the communication and develop ment of novel concepts. The format ofthe content ofthe volume is similar to that ofthe Symposium and addresses, in separate parts: Numerical Fluid Dynamics, Interactive Steady Boundary Layers, Singularities in Unsteady Boundary Layers, Transonic Flows, and Experimental Fluid Dynamics. The motivation for most of the work described relates to the internal and extern al aerodynamics of aircraft and to the development and appraisal of design methods based on numerical solutions to conservation equations in differential forms, for corresponding components. The chapters concerned with numerical fluid dynamics can, perhaps, be interpreted in a more general context, but the emphasis on boundary-Iayer flows and the special consideration oftransonic flows reflects the interest in external flows and the recent advances which have allowed the calculation methods to encompass transonic regions.


Unsteady Viscous Flows

Unsteady Viscous Flows

Author: Demetri P. Telionis

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 429

ISBN-13: 3642885675

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Most of the fundamental concepts of unsteady viscous flows have been known since the early part of the century. However, the past decade has seen an unprecedented number of publications in this area. In this monograph I try to connect materials of earlier contributions and synthesize them into a comprehensive entity. One of the main purposes of a monograph, in my opinion, is to fit together in a comprehensive way scattered contributions that provide fragmented information to the readers. The collection of such contributions should be presented in a unified way; continuity of thought and logical sequence of the presentation of ideas and methods are essential. The reader should be able to follow through without having to resort to other references, something that is unavoidable in the case of a research paper or even a review paper. Many of the solutions discussed in the literature address specific practical problems. In fact, in the process of collecting information, I discovered independent lines of investigations, dealing with the same physical problem, but inspired by different practical applications. For example, I found that two groups of investigators have been studying independently the response of a viscous layer to a harmonic external disturbance. One group is con cerned with mass transport and the transport of sediment over the bottom of the ocean, and the other is interested in the aerodynamics of lifting surfaces in harmonically changing environments.