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Description:
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This thesis presents the development of calibration and data -reduction algorithms for non -conventional multi -hole pressure probes . The algorithms that have been developed for conventional 5 - and 7 -hole probes are not optimal for probes with port arrangements (on the probe tip ) that are non -conventional . Conventional algorithms utilize the axisymmetry of the port distribution pattern to define the non -dimensional pressure coefficients . These coefficients are typically defined specifically for these patterns , but fail to correctly represent different patterns of port arrangements , such as patterns without axisymmetry or regularity . The algorithms introduced herein can handle any pattern of port arrangement , from axisymmetric and regular to random . Moreover , they eliminate the need to separate the measurement domain of a probe to "low -angle" and "high -angle" regimes , typical in conventional 5 - and 7 -hole -probe algorithms that require two different sets of pressure coefficient definitions and procedures . Additionally , the algorithms have been formulated such that they facilitate redundancy implementations , especially in applications where such redundancy is important , such as air -data systems . The developed algorithms are first applied to a non -conventional probe , a nearly omni -directional 18 -hole probe , and demonstrate very high flow measurement accuracy . Subsequently , the algorithms were applied to a new 12 -hole , nearly omni -directional , flow velocity measurement probe capable of measuring reversed flows . The new 12 -hole design offers several advantages over a previously developed , 18 -hole , nearly omni -directional probe . The probe is optimized in the sense that , regardless of the flow direction , it allows calculation of the 4 unknown flow quantities , i .e . the two flow angles , the velocity magnitude and the static pressure , with the minimum necessary number of holes /ports on the probe tip . This probe also has a non -conventional arrangement of its pressure ports and therefore the new calibration and data -reduction algorithms can be effectively employed . With theoretically generated pressure data for the 12 -hole probe , the coefficient definitions are analyzed and found to be well -behaved . |