The rapid development and improvement of computational simulation analysis codes coupled with improved performance of modern computers, increases the scope of fluid dynamics, structural, and heat-transfer problems which can be addressed. At the same time, propulsion systems have become increasingly complex as mission criteria push the limits of present technologies. These propulsion system advancements require detailed understanding of engine performance and test cell interactions. Accordingly computational simulation capability is growing into a role which complements and enhances many phases of engine system design, including test and evaluation. At the Arnold Engineering Development Center (AEDC) computational analyses have become an integral part of the hardware testing process by providing information for pretest facility design; instrumentation; and posttest analysis to reduce risks and improve test facility capabilities.