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Title: CFD-Assisted Calibration of a Multi-Hole Probe for a Small UAS
A method for calibrating a multi-hole probe (MHP) used for inertial wind vector measurements from a small Uncrewed Aircraft System (sUAS) is presented. The first phase of the calibration process is broken into three parts: Obtaining reference airspeed, angle of attacks and side slip angles; calibrating MHPs with experimental data; mitigating bias errors to improve calibrations.The method follows the established wind tunnel calibration procedures and includes two additional steps to increase calibration accuracy. The calibration process begins with a computational fluid dynamics (CFD) study on blockage effects in the wind tunnel. CFD results indicate nontrivial deviations of the mean flow due to blockage in wind tunnel test section. Analysis shows a linear relationship between experimental setup position and the resulting deviation from unidirectional flow. The relationship is incorporated into the routine to develop a calibration model. This augments previously demonstrated techniques by processing experimental data from the probe using CFD results. Then the model is refined by removing experimental bias angles. The next phase is to account for upwash effects caused by the sUAS lifting surfaces. Initial CFD analysis has been conducted to determine the relationship between the perceived airframe orientation measured from the relative wind, and the angle of attack measured by the MHP. Preliminary results show that there is a measurable linear relationship between the perceived and actual angles of attack. The objective these additional steps is to increase the accuracy of MHP calibration and characterize the error in inertial wind vector measured during field experiments.  more » « less
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AIAA SciTech 2022 Forum
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National Science Foundation
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