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ESDU 90020

90th Edition, March 1, 2009

Complete Document

Airframe-induced upwash at subsonic speeds

Includes all amendments and changes through AB, March 1, 2009

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Product Details:

  • Revision: 90th Edition, March 1, 2009
  • Published Date: March 1, 2009
  • Status: Active, Most Current
  • Document Language: English
  • Published By: Engineering Sciences Data Unit (ESDU)
  • Page Count: 86
  • ANSI Approved: No
  • DoD Adopted: No

Description / Abstract:


This Item provides a simple theoretically-based method for predicting the airframe-induced upwash at any point in the flowfield ahead of the wing at subsonic speeds. The airframe can be considered to consist of "wing-like", essentially planar, lifting components, and "body-like", essentially non-lifting, components. The method, detailed in Section 3, consists of a means of predicting the upwash due to these two classes of airframe component in isolation, together with an approximate means whereby account is taken of interference effects between the various components. The method is therefore capable of application to a wide range of airframe configurations.

The method, commonly called the "Yaggy-Rogallo" method, although originally developed for application to the propeller vibration and flutter problem (Derivation 4), is applicable to any area requiring a knowledge of upwash flow fields. Such areas could include jet engine inlet flows, the local flow around canards, boom-mounted sensors and fuselage-mounted or underwing-mounted stores, for example.

The applicability and accuracy of the method are discussed in Section 4. In particular, Section 4.2.3 describes two extremes of application for which the method has already been used. The Derivation and References are given in Section 5 and worked examples illustrating two of the many possible uses of the method are provided in Section 6. Material supporting the implementation of the method is given in Appendices A, B and D. Details of a computer program for the method, ESDUpac A9020, are given in Appendix C.