Uncertainty Analysis of Inlet Dynamic Flow Distortion Using an Analog/DigitalHybrid Editing System

摘要

The objectives of this analysis were to establish precision and bias errors foran analog/digital hybrid computer system (DYNADEC) used in the dynamic data editing phase of inlet wind tunnel testing. An uncertainty analysis was initiated to evaluate the system using inlet data from the Aeronautical Systems Center (ASC)/ Arnold Engineering Development Center (AEDC) Freejet Development program. Three test points from a subscale freejet test and three test points from a wind tunnel test of the same F-15 inlet model were selected to cover a wide range of test conditions and turbulence levels. Precision errors of the 40 total pressure probes at the location of the engine face were 1-2% of the 40 total pressure recovery magnitudes. Precision errors of the Pratt and Whitney K a2 distortion index, the parameter used to edit the data on DYNADEC, were also investigated. These results indicated that K a2 precision errors decreased with higher turbulence levels. Static bias errors were also computed by sending known signal through the DYNADEC system and measuring the output quantity. Static bias errors were much smaller in comparison to the precision error magnitudes and may be considered negligible.... Distortion, Bias, Uncertainty, Precision, Error, Inlet.