Description: The proposed innovation is a simple, robust, self-contained, and self-powered sensor array for the detection of laminar/turbulent transition location, areas of flowfield separation, and shock wave locations. The system can be used for both flight test andin ground test facilities. The proposed system uses a very robust and proven sensor technology combined with a novel mounting and manufacturing technique. The sensor array is reusable and requires no calibration, external power source or acquisition system. The system combines an array of small, surface flush, sensors embedded in an extremely thin, flexible polyimide strip coupled with a self-contained, battery powered acquisition, reduction, and storage system. The system operates by sensing changes in local heat transfer within the boundary-layer. Variations in heat transfer due to the state of the boundary layer (laminar, transitional, turbulent, separated regions) produce changes in the sensor output. Other flowfield features where heat transfer is affected will also be discernable, such as shock waves. The flush mounted sensors, embedded in a smooth, thin polyimide sheet, conform to the local surface contour and produce minimal aerodynamic interference, allowing non-intrusive measurements. The system will be quantitatively accurate across the low-speed through supersonic flow regime. No external power or control is required for operation. After testing, the system can be quickly removed and reused. Compared to current systems designed for similar measurements, the proposed system promises to provide a significantly more robust and efficient system in a relatively simple, cost effective package.

Benefits: A robust measurement system capable of determining transition location, separation, and shock locations for both flight and ground test facilities has significant potential application at several NASA centers, and across a wide range of NASA facilities. The accurate determination of boundary-layer transition and separation locations can be used to validate computational fluid dynamics models, transition prediction, and multidisciplinary analysis and optimization tools. The system could be used in boundary-layer ingestion and optimization efforts. In a more permanent set-up, the robust measurement system could be used as input for vehicle adaptive control in uncertain environments or adverse conditions, or for closed loop flow control for aircraft, rotorcraft, or high lift technologies. The measurement system's relatively simple, robust technology, coupled with its reusable nature make it a very attractive, cost effective system. With the significant push for increased efficiency and reduced fuel consumption, laminar flow, and increasing its extent on aircraft surfaces is a fundamental aerodynamic goal. The proposed measurement system will help NASA meet both the Environmentally Responsible Aircraft (ERA) and Subsonic Fixed Wing Project goals.

Advanced sensing technology for both flight and ground test facilities that can determine transition location, regions of separated flow, and the locations of shock waves will provide RHRC with a unique and highly marketable product. The ability to measure laminar/turbulent transition and separation locations will be of significant importance to both test engineers and researchers. With the current high costs of both flight and ground testing, coupled with reduced design and test schedules, the proposed technology will be highly desirable in military, government, and civilian testing markets. The technology developed by RHRC and Q-flex under this program will allow efficient and cost effective measurements on vehicles across a wide range of applications other than aircraft. These include automobiles and hydrodynamic applications. RHRC and Q-flex will be able to provide complete sensor systems. The technology can also be easily licensed. Any surface where aerodynamic performance is a concern is a potential application of the technology. The technology has a very large audience in both government and commercial research and development.