Viscous-inviscid interactions in external aerodynamics

• Published in: Progress in aerospace sciences Vol. 24; no. 2; pp. 51 - 171
• Main Authors: Lock, R.C., Williams, B.R.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 1987
• ISSN: 0376-0421; 1873-1724
• DOI: 10.1016/0376-0421(87)90003-0

After a short introduction, Section 2 provides a physical background to the subject of viscous-inviscid interactions (VII). Section 3 covers the basic theoretical principles of interactive methods in two dimensions: generalisations of the concept of the displacement effect and the momentum integral equation; the effect of normal pressure gradients; matching conditions in the wake. The boundary conditions required for the equivalent inviscid flow (EIF) are then summarised, and the section concludes with a brief discussion of some relevant features of ‘integral’ and ‘differential’ methods for turbulent boundary layers. In Section 4 a similar, though necessarily incomplete, account is given of the corresponding treatment in three dimensions. Section 5 describes the principles of techniques for coupling the viscous and inviscid components of an interactive method; first in general principles and then in greater detail. In Section 6 a number of recent VII methods are reviewed and compared with experiment: first in two-dimensional incompressible flow (single and multiple aerofoils); then for aerofoils in transonic flow; an example of axisymmetric transonic flow; and finally methods for three-dimensional wings in transonic flow. The conclusions briefly summarise the current situation regarding the development of VII methods, and consider future possibilities in the subject.