The Use of Trademarks Or Names O F Manufacturers I N

Abstract

this report is for accurate reporting and does not constitute an official endorsement, e ither expressed or i mplied, o f such products or manufacturers by the Nationa l Aeronaut ics and Space Administration. This publication i s ava il able f rom the f ol lowing sources: NASA Center for AeroSpace Information National Technical Information Service (NTIS) 800 Elkridge Landing Road 5285 Port Royal Road Linthicum Heights, MD 21090-2934 Springfield, VA 22161-2171 (301) 621-0390 (703) 487-4650 Introduction Computational fluid dynamics (CFD) methods and advanced turbulence models are needed to predict propulsion aerodynamic effects in transonic and supersonic free-stream conditions. Analytical results are frequently used to supplement the experimental data in critical design decisions. Accurate prediction of the pressure distribution and the skin friction coefficient is paramount to the design of propulsion systems. In the area of propulsion integration, accurate predictions of boundary layer structure, skin friction, and flow separation by CFD methods are critical. Two-equation turbulence models (ref. 1) offer several advantages over other approaches that compute practical flow problems. For example, algebraic models lack turbulence history-dependent nonlocal effects (through the convection and viscous diffusion of the Reynolds stress models), effects which are known to be important in determining the turbulence structure in complex flows. The numerical calculations that use the more advanced Reynolds stress models (refs. 2 and 3) require the solution of transport equations for each component of the Reynolds stress tensor in addition to solution of the NavierStokes equations; this approach requires tremendous computational time for three-dimensional flow problems. The tran..