Innovative Aerodynamic Measurement for Integrated Hypersonic Inlets

Hypersonic propulsion systems are Hypersonic propulsion systems are characterized by high Mach number gas flows over vehicle surfaces and internal ducts. The flow often includes shock waves, shear layers, vortices, and separated flows. The ability to measure surface quantities such as pressure and skin friction on a hypersonic inlet model would provide increased insight into the complex flow characteristics that govern inlet performance. Unfortunately, nonintrusive sensors require optical access that has been difficult to obtain. Optical sensors for measurements of pressure (Fast Pressure Sensitive Paint) and skin friction (Surface Stress Sensitive Films) offer non-intrusive measurements on surfaces, exactly the capability that is needed to study hypersonic inlets. Unfortunately, the size of the cameras and light sources that are used in these systems have precluded their use in regions like an internal duct. During the past several years, camera and LED technology has evolved dramatically resulting in small packages for both imaging and illumination. Combining this new hardware with state-of-the-art optical technology for fast PSP and S3F measurements will result in a pair of sensors that can be miniaturized and utilized for non-intrusive measurements in traditionally inaccessible regions of the model. These measurements include continuous distributions of skin friction and unsteady pressure. BENEFIT: There is considerable interest in measurements of unsteady pressure and skin friction for evaluation of computational models and study of flow physics on hypersonic inlets, compressors, and other wind tunnel models with limited optical access. This system will provide advancement of the state-of-the-art in this field as the proposed research will develop a system for the measurement of continuous distributions of skin friction and pressure using a miniaturized imaging system for data acquisition. This miniaturized imaging package, and the associated Furthermore, the proposed technology is an optical sensor that is applied using spray coating techniques, and therefore, the sensor can be applied without modification to the model design.