Introduction

This part introduction presents some of the key concepts discussed in the subsequent chapters of this book. The part attempts to review progress in the field of computational aerodynamics; earlier work is occasionally included whenever considerations of logic and coherence so demand. It considers the studies concerned with the boundary layer and viscous shock layer models. The boundary layer equations are essentially the asymptotic form assumed by the NS equations in the limit as the flow Reynolds number tends to infinity. The part discusses the flowfields modeled by the parabolized Navier-Stokes (PNS) equations. The viscous hypersonic studies employ the so-called PNS equations, a more sophisticated model obtained from the full NS equations by neglecting molecular transport in the main (marching) direction over the entire disturbed layer, including the shock wave structure. The part examines the solution of the full set of NS equations. It reviews a number of three-dimensional problems based on the full system of NS equations.