Future Air Force platform requirements will drive innovations in propulsion systems to ensure reliable thrust levels under all operating conditions. Current propulsion system development methodologies do not fully consider the integration influences between platform and propulsion system. A systems engineering approach is necessary if future requirements are to be met. This approach requires that a fundamental understanding be developed of the interactions that are present between the propulsion system and the platform. This is critical regardless of mission requirement, as most, if not all missions will require complex platform maneuvers or as a minimum reduced frontal area, which drive significant changes to the propulsion system inlet boundary conditions. When an air-breathing propulsion system is integrated in an airframe, the air inlet flow to the propulsion system is disturbed. This can lead to reduced performance, life, and reliability of the propulsion system. Research is needed to provide fundamental information to avoid or mitigate these problems within the propulsion system.

The current missing fundamental pieces of information, where research is desired, are as follows: (1) Are all flow-fields presented as boundary conditions from a platform similar enough that a propulsion system could be designed to accommodate all? (2) How important are the length scales both temporal and spatial of the boundary flow in driving propulsion instability? (3) How great is the interaction between these coupled systems? (4) What are the key fluid mechanical properties of the boundary flow presented by the platform that drive propulsion instability or performance loss--Potential or Kinematic (i.e., Total Pressure Field or Vorticity field)?

Research assistance in any of these areas is desired.

References

Fidalgo VJ, Hall CA, Colin Y: Journal of Turbomachinery 134(5): 051011, 2012

Sheoran Y, Bouldin B, P. Krishnan PM: Journal of Turbomachinery 134(4): 041008, 2011

Yao J, Gorrell SE, Wadia AR: Journal of Turbomachinery 132(4): 041014, 2010