Unsteady Flow Analysis on Inlet and Exhaust System Distortion and Structural Analysis for Modern Propulsion Systems

Modern aircraft and rotorcraft feature tightly integrated propulsion systems, with engine inlet and exhaust geometries that are complex and designed to meet multiple objectives. Unsteady flows through the propulsion system resulting from maneuvers or periodic shedding within the system can lead to undesirable engine surge, stall, or vibrations that may result in damage. In addition, unsteady inlet distortion is typically characterized using wind tunnel and flight testing, where instrumentation and data collection is costly. With these motivations, multidisciplinary analysis and optimization tools are needed which can accurately predict the phenomena associated with engine transients, vibration, and other structural responses.Computational Fluid Dynamics (CFD) codes employing the Large Eddy Simulation (LES) methodology have proven capable of accurately predicting the unsteady nature of turbulent flows found in modern aircraft. Coupling such methods to finite element analysis (FEA) tools is a viable path towards the reliable prediction of unsteady structural loads that may be employed earlier in the design cycle, reducing development and possible repair and replacement costs. The proposed Phase II program builds upon prior experience and developments made by CRAFT Tech in the areas of LES and fluid/structural interactions (FSI), with an emphasis on validation.