Utilizing active flow control on civil transport aircraft flaps has been shown to delay stall at low aircraft speeds. This can lead to reducing the size of or removing flaps from aircraft, which then can reduce the part count, weight, and manufacturing cost of the aircraft. The effect of material, manufacturing process, and dimensional variation on these parts is not entirely known.
In this work, the key performance characteristics, also referred to as the functional requirements of the AFC, were identified to be the coefficient of momentum, the oscillation frequency, and the fluidic power requirement. The operational requirements of the AFC were identified to be the ability to withstand pressure, significant temperature variations, and fluctuations in humidity. The materials that are explored include aluminum and carbon fiber PEKK. The manufacturing processes that were explored include machining, selective laser sintering (SLS), stereolithography (SLA), and injection molding. Variations in the dimensions were explored: nozzle width, nozzle length, nozzle radius, nozzle symmetry, nozzle curvature, and interaction chamber width. These were tested using a bench test setup.
It was discovered that material had no impact on the performance of the AFC. The manufacturing process did affect the performance of the AFC. The changes included the inability of SLS, SLA, and injection molding to produces edges as sharp as can be produced by machining. As a result, the devices had lower pressure drops and higher oscillation frequencies. It was also identified that nozzle width, shoulder length, and nozzle radius affected the oscillation frequency and that the nozzle width and nozzle radius affected the pressure drop. Nozzle symmetry and nozzle length did not affect the oscillation frequency and pressure drop; however, they did affect the jet profile. Using this information, a dimensionless model was developed that can be used by AFC designers.