Analysis of Low Speed Unsteady Airfoil Flows

And therefore require the use of Reynolds averaging in order to evolve a practically useful computational tool. For these reasons, the second chapter begins with a presentation of the Navier-Stokes equations and their Reynolds-averaged form.

Furthermore, since many flows can be analyzed efficiently by the use of reduced forms of the Navier-Stokes equations, the thin-layer Navier-Stokes, boundary layer and inviscid flow equations are also included in this chapter.

Since inviscid, boundary ayer, and Navier-Stokes methods are now widely used, separate chapters are devoted to describe the three methods for the computation of steady and unsteady airfoil flows. The computation of inviscid airfoil flows benefited enormously, both conceptually and computationally, by the introduction of the so-called panel method, pioneered at the Douglas Aircraft Company in the 1960s.

Thus, a panel method for the calculation of the flow over an airfoil executing a general time-dependent motion s described in chapter three. It is known that the viscous flow effects can be included with the pressure distribution obtained from an inviscid flow solution as input into the boundary layer equations. This concept can be further refined by interaction between the inviscid and boundary layer computations, thus making it possible to analyze mildly separated flows as described in chapter five.

The fourth, sixth and seventh chapters describe applications of the inviscid, boundary layer and viscous- nviscid interaction codes, respectively, to provide the reader with an appreciation for the usefulness and range of validity of each method by comparing the computations with available experimental results. The eighth and ninth chapters consider the analysis of strongly viscous and separated flows by means of the Reynolds averaged Navier-Stokes equations by describing first the various solution methods for both incompressible and compressible flows and t