For classified documents, follow the procedures in DoD 5220.22-M, Industrial Security Manual, Section 11-19 or DoD 5200. I-R, Information Security Program Regulation, Chapter IX. For unclassified, limited documents, destroy by any method that will prevent disclosure or reconstruction of the document. APPROVAL STATEMENT This report has been reviewed and approved.

Two primary aircraft propulsion subsystems are the inlet and the engine. Traditionally these subsystems have been designed, analyzed, and tested as isolated systems. The interaction between the subsystems is modeled primarily through evaluating inlet distortion in an inlet test and then simulating this distortion in engine tests via screens or similar devices. Recently, it has been recognized that significant improvements in both performance and operability can be realized when both the inlet and the engine are designed with full knowledge of the other. In this paper, a computational tool called Turbine Engine Analysis Compressor Code (TEACC) is used to evaluate the effect of inlet distortion on a three-stage military fan. This three-stage military fan is further connected to an F-16 inlet and forebody operating at an angle of attack and sideslip to demonstrate the effect of inlet distortion generated by flight maneuvers. The computational approach of simulating an integrated inlet-engine system is expected to provide additional insight over evaluating the components separately.

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The development of high-performance aircraft demands the successful integration of the airframe, engine, and control systems. Advancements in aircraft technologies bring with them the need to improve the computational and experimental tools applied to the airframe-engine compatibility evaluations. This paper focuses on the need to improve one of these tools, the direct-connect turbine engine test method. In particular, the paper advocates improving the direct-connect test simulation of the total-pressure distortion induced in flight by the external airframe and the inlet system. To meet the needs of future direct-connect tests, AEDC embarked on the development of a transient total-pressure distortion generator. The paper first introduces specific total pressure pattern simulation requirements that form the basis for the development and results of the distortion generator development process. Included are sample distortion generator concept test results and a description of a fully functional prototype that is in fabrication. Next, the paper summarizes a parallel development of computational fluid dynamics (CFD) tools that will be applied to adapting the prototype design to specific test facilities and to the operation of the distortion generator in turbine engine tests. The paper concludes with a look ahead from the total-pressure distortion methodology to test and computational methodologies for other parameters, with emphasis on swirl.

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