Advanced Flow Control and Modeling/Prediction Technologies for Efficient Integration of Offset Diffusers in Supersonic Inlets
Abstract
Major advancements in inlet integration technologies are needed to obtain optimal operationalcharacteristics with low development risk/costs over the full flight envelope of next-generationcarrier-based CV aircraft. These Navy aircraft will use embedded adaptive" engines to attain bothaerodynamic efficiency and small spot factor with extremely compact inlet systems that will beoffset, poten""tially in multiple planes to enable efficient inlet/airframe integration schemes. Therealization of these compact, offset inlet sys""tems poses significant technical challenges in terms offlow management in the inlet aperture and the compact, subsonic offset diffu""ser that are affected byshock waves, concentrated streamwise vortices, and internal flow separation. The resulting totalpressure l""osses and flow distortion at the engine face can severely compromise engine operabilityand performance, and may cause aeromechanica"l damage to turbine blades. Active flow control(AFC) offer unique potential for management of these complex flows to mitigate their" adverseeffects on the performance of the propulsion system, and the realization of adaptable inlet with fewor no moving parts.Ea"rlier ONR-supported investigations at Georgia Tech demonstrated the utility of fluidic-based AFCfor controlling internal flow separ"ation in an aggressive, three-dimensional, offset isolated diffuser.Actuation significantly alters the internal structure and evolu""tion of secondary flow, and leads tosubstantial reduction in averaged pressure distortion, in excess of 60% at the AIP. Georgia Tec"h andthe Boeing Company propose a three-year closely-coupled experimental and computational researchprogram that will build on the"se earlier findings, and will focus on implementation of advanced,fluidic-based flow control approaches for adaptive-performance in"let system in which the diffuser isintegrated with an inlet aperture. The joint experiments and simulations will identify and corroboratesalient flow mechanisms that give rise to flow distortion and how they can be temporally andspatially mitigated by AFC. The proposed experimental investigations at Georgia Tech emphasizeAFC based on fluidic modification of the ~apparent~ aerodynamic shape of the diffuser to alter thespatial and temporal evolution of surface vorticity layers and suppress or eliminate local separation",and control the evolution of secondary flow vortices. A crucial element of the proposed research isBoeing~s development of high-f""idelity CFD prediction and modeling tools, closely-coupled toexperiments at Georgia Tech. Findings from the numerical investigation""s, combined with highqualitydata provided by experiment, will aid development of next-generation turbulence models thatovercome pr"edictive limitations of current CFD codes.The overarching goal of the proposed 3-year experimental/numerical program is to demonstrate theeffectiveness of integrated AFC for adaptively improving the overall performance in a diffuser thatis fully-integrated with" an inlet aperture (0.7 < Mthroat < 0.75). Specifically, we focus on control ofthe shock waves formed by local expansions in the th""roat region and their interactions with thediffuser boundary layer, followed by development of AFC methodologies for controlling st"reamwisevortices that form at takeoff conditions and low flight speeds on the inside surface of swept cowllips. The experimental data will be used to hone numerical tools (including turbulence models) foraccurate simulation of these complex internal flows. The investigations will culminate withdemonstration of actuation effectiveness in the fully integrated diffuser. The proposed investigationswill be conducted in close collaboration with personnel at NAVAIR throughout the programduration. The proposed work will pro"vide validated, high-fidelity computational tools that will helpimprove system trades for AFC-enabled advanced-inlet concepts in a" range of supersonic andsubsonic fixed-wing aircraft.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 05, 2017
- Source ID
- N000141712537
Entities
People
- Ari Glezer
Organizations
- Georgia Tech Research Corporation
- Office of Naval Research
- United States Navy