SCIENTIFIC AND TECHNICAL AEROSPACE REPORTS

A Biweekly Publication of the National Aeronautics and Space Administration
VOLUME 44, ISSUE 8 - April 21, 2006

02 AERODYNAMICS
Includes aerodynamics of flight vehicles, test bodies, airframe components and combinations, wings, and control surfaces.

Also includes aerodynamics of rotors, stators, fans, and other elements of turbomachinery.

For related information see also 34 Fluid Mechanics and Thermodynamics.

20060010492 Office National d'Etudes et de Recherches Aeronautiques, Toulous, France

Laminar-Turbulent Transition and Shock Wave/Boundary Layer Interaction

Arnal, Daniel; Delery, Jean; Critical Technologies for Hypersonic Vehicle Development; December 2005, pp. 4-1 - 4-46; In English; See also 20060010486; Original contains black and white illustrations; Copyright; Avail.: CASI: A03, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document

Part A: Laminar-turbulent transition. Laminar-turbulent transition strongly affects the wall heat flux of high speed vehicles. The first part of this Lecture is devoted to the description and the modelling of some transition mechanisms. The transition process dominated by the amplification of unstable waves is considered first, with emphasis on the linear stability theory. It is also shown that a major difference between transition in two- and three-dimensional flows lies in the receptivity phase. Then the problem of boundary layer tripping by large roughness elements is briefly addressed. Part B: Shock wave/boundary layer interaction. Shock wave/boundary layer interactions (SWBLI) in hypersonic flows are characterized by extremely large pressure variations and intense wall heat transfer, especially when the shock is strong enough to separate the boundary layer. The second part of the Lecture focuses on the physical properties of SWBLI induced by a ramp or an impinging-reflecting shock, emphasis being placed on hypersonic interactions. A special attention is paid to thermal effects associated with hypersonic SWBLI. The difficulties raised by SWBLI modelling in high Mach number flows are shortly discussed. Derived from text

Turbulent Boundary Layer; Laminar Flow; Shock Waves; Three Dimensional Flow; Temperature Effects; Surface Roughness; Boundary Layers; Hypersonic Flow; Transition Flow

20060010493 Eloret Corp., Sunnyvale, CA, USA

System Design Constraints - Trajectory Aerothermal Environments

Prabhu, Dinesh K.; Critical Technologies for Hypersonic Vehicle Development; December 2005, pp. 7-1 - DP-29; In English; See also 20060010486; Original contains color and black and white illustrations Contract(s)/Grant(s): NAS2-99092; Copyright; Avail.: CASI: A03, Hardcopy; Available from CASI on CD-ROM only as part of the entire parent document

The primary concern of aerothermodynamics, as applied in the design of hypersonic flight vehicles, is to predict the heating experienced by the vehicles as they lose their high kinetic energy due to aerodynamic drag (see Ref. 1 for a broader discussion of aerothermodynamics). The past approach to the problem of aeroheating prediction has been one based on approximations/correlations derived from hypersonic boundary-layer theory [2] applied to simple geometric shapes such as flat plates, spheres and sphere-cones. Approaches based on Computational Fluid Dynamics (CFD), which enables solution of the complete Navier-Stokes equations, were usually used to verify the aerothermal design. The availability of fast, large-scale, and relatively inexpensive computing hardware, coupled with maturation of numerical methods and advances in modeling of hypersonic shock layers, has made it possible to predict the heating environments with good accuracy and detail using methods of CFD. CFD has now become an integral part of the design process. Derived from text

Aerothermodynamics; Aerodynamic Heating; Aerodynamic Drag; Computational Fluid Dynamics; Design Analysis; Hypersonic Shock; Hypersonic Vehicles

Source: NASA