Description: Clear Science Corp. proposes to develop and demonstrate computational fluid dynamics (CFD)-based software for designing and evaluating active flow control (AFC) systems on aircraft. The software will facilitate the identification of optimal types of actuation and their locations, will support virtual flight testing with both open- and closed-loop control systems, and will enable quantitative trade studies that compare performance enhancements through AFC to the costs of control. In subsonic, transonic, and supersonic applications, AFC systems can improve air vehicle performance by reducing and/or eliminating separation and increasing circulation---resulting in smaller control surfaces, less weight, lower drag, and less fuel consumption. Many AFC applications involve highly unsteady flow dynamics with turbulence, unsteady shocks, separation, and aeroservoelasticity interacting in complex ways that render open-loop systems either ineffective or too costly in terms of energy, weight, and volume. For this reason, closed-loop AFC system design will be a critical area of focus in the proposed project. Components of closed-loop systems include dynamical and measurement-based state estimators, regulators, and compensators. The proposed AFC system design and analysis software will be developed using the X-56 experimental aircraft as a demonstration platform, a long-range, highly flexible air vehicle currently under development at the NASA Armstrong Flight Test Center.

Benefits: The proposed AFC design and system integration software, using the X-56 as a demonstration platform, targets key aspects of the NASA ARMD Strategic Thrust 3A: Ultra-Efficient Commercial Vehicles Subsonic Transport. The scope of the thrust covers fixed wing commercial vehicles carrying passengers and cargo in both civil and military capacities. The objective is pioneering technologies for big leaps in efficiency and environmental performance: environmental compatibility while reducing cost, increasing range, and maintaining safety. The technology is also an enabler for NASA ARMD's Strategic Thrust 2: Innovation in Commercial Supersonic Aircraft. The targeted "ultra-efficient" vehicles will use less energy with less emissions and lower perceived noise. The centerpiece of NASA's 10-year acceleration for advanced technologies testing is New Aviation Horizons (NAH), consisting of a suite of future X-planes that include hybrid electric, wing-body, and quiet supersonic demonstrators. These constitute potential Phase III applications through direct contracts with NASA and through collaborations with its industry and university partners.

Clear Science Corp.'s AFC software is enabling technology with applications, first, inside NASA and the Department of Defense (DoD) during development of new ultra-efficient, subsonic air vehicles, and, second, among aircraft manufacturers as these vehicles reach the commercial market. The proposed project will focus on the experimental X-56 program with much broader potential applications relating to active flow control. These include flutter suppression and gust load alleviation in other types of subsonic, highly flexible airframes, aerodynamic, aeroelastic, and aeroservoelastic flow control in highly maneuverable fighter aircraft operating in the subsonic, transonic, and supersonic regimes (with shocks and shock-boundary layer interactions), aerodynamic and aero-optical flow control in fixed-wing aircraft and rotorcraft, and aerothermodynamic flow control in hypersonic air vehicles. The AFC technology to be developed in the proposed project and demonstrated with the subsonic X-56 is directly applicable to higher-speed air vehicles. Phase III product development would extend the scope of application to a wide range of commercial and military aircraft, both manned and unmanned.