The Oxford Probe: an open access five-hole probe for aerodynamic measurements

Hall, Benjamin F.; Povey, Thomas

doi:10.1088/1361-6501/aa53a8

Cited by 29 publications

(29 citation statements)

References 8 publications

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“…During the development of the Oxford Probe, it was observed that the Reynolds number sensitivity of the calibration map was small for Re D > Re D,crit = 1.5 × 10 4 [7]. This Reynolds sensitivity threshold is in accordance with previous research (e.g.…”

Section: Introductionsupporting

confidence: 91%

“…Perhaps the most common type, in applications where the entire flow structure is to be assessed, is the five-hole probe, which is widely used in turbomachinery surveying applications. Turbomachinery flows are generally characterized by Reynolds numbers in the range 10 5 < Re L < 10 7 , where we set L to an arbitrary value of order 50 mm, which is of the order of the chord length of a nozzle guide vane or rotor blade [2,3]. This represents a Mach number range of 0.3 < M < 1.3.…”

Section: Introductionmentioning

confidence: 99%

“…The concept of using both additive manufacturing and a common calibration map (pre-determined based on calibrations for identical geometries) to dramatically lower the complexity and cost of multihole probes was explored by Hall and Povey [7] who proposed and developed an open-access five-hole probe. This was called the Oxford Probe, for which the design, manufacture files, calibration, and processing routines are available under a creative commons license (free for non-commercial use).…”

Section: Introductionmentioning

confidence: 99%

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Effect of Reynolds Number on Five-Hole Probe Performance: Experimental Study of the Open-Access Oxford Probe

Passmann

Wiesche

Povey

et al. 2021

Journal of Turbomachinery

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There is relatively little literature concerning the effect of Reynolds number on multihole aerodynamic probe performance. In particular, there is almost no discussion in the literature regarding the underlying mechanisms of Reynolds number (Re) sensitivity for such probes. In order to close this gap, detailed investigations of the effect of Re on a five-hole probe have been performed using both PIV techniques and oil flow visualizations. Wind- and water-tunnels were used to cover a wide range of Re. The open-access Oxford Probe was used for these studies because of the readily available data-sets and processing routines, and to allow future comparisons by other authors. Complex flow dynamics including flow separation and re-attachment were identified, which cause Re-sensitivity of the calibration map at low Re even for low yaw or pitch angles. By comparing calibration maps across a wide range of Re, we demonstrate that the Oxford Probe can be employed without much loss of accuracy at lower Re levels than initially (conservatively) suggested, and quantify the errors in the extreme low-Re regime. Overall we demonstrate the robustness of the Oxford Probe concept across a wide range of Re conditions, we more clearly defined the low-Re limit for the probe design and quantify errors below this limit, and we illustrate the fundamental mechanisms for Re-sensitivity of multi-hole probes.

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Section: Introductionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Reynolds Number on Five-Hole Probe Performance: Experimental Study of the Open-Access Oxford Probe

Passmann

Wiesche

Povey

et al. 2021

Journal of Turbomachinery

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“…The three-hole probe was calibrated over a Mach number range of 0.3-0.7 and a yaw angle range of ±40 deg using the Oxford Probe Calibration Facility, described in Ref. [15]. The frequency responses of the three-hole probe and thermocouple probes measurements were independently estimated to be approximately 100 Hz, based on experimentally validated analytical predictions described in Refs.…”

Section: Coolant Supply and Mass Flowmentioning

confidence: 99%

Impact of Rotor-Casing Effusion Cooling on Turbine Performance and Operating Point: An Experimental, Computational, and Theoretical Study

Adams

Adami

Collins

et al. 2021

Journal of Turbomachinery

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It is known that a secondary effect of rotor-casing effusion cooling is to modify and potentially spoil the rotor over-tip leakage flow. Studies have shown both positive and negative impacts on high-pressure stage aerodynamic performance and heat transfer, although there remains no consensus on whether the net effect is beneficial when both aerodynamic and thermal effects are accounted for simultaneously. An effect that has not been extensively discussed in the literature is the change in stage operating point that arises due to mass introduction midway through the machine. This effect complicates the analysis of the true performance impact on a turbine and must be accounted for in an assessment of the overall benefit of such a system. In this paper, we develop a low-order (mean-line) analysis in an attempt to bring clarity to this issue. We then present results from experiments conducted in the Oxford Turbine Research Facility, a 1.5-stage transonic rotating facility capable of matching non-dimensional engine conditions, with effusion cooling implemented over a sector of the rotor casing. Finally, we present steady and unsteady Reynolds-Averaged Navier-Stokes (RANS) simulations both with and without cooling. The results are used show that with cooling, there are flow changes both locally to the cooled casing (changes to the tip-leakage and secondary flow structures) and globally (changes to the bulk-flow velocity triangles). For the present configuration, both changes contribute positively to stage efficiency.

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“…Cone tips, on the other hand, are generally fully calibrated in the wind tunnel and the cone angle allows for an adjustment of the angle-sensitivity of the measurement. An overview of relevant geometries and aerodynamic probe design, can be found e.g., in the study of Hall and Povey [38]. MASC uses a five-hole probe ( Figure 2) with a tip diameter of 4 mm, a cone angle of φ = 60 • , forward facing holes and is calibrated from −20 • to 20 • .…”

Section: Five-hole Probe "Pressures-to-airflow-vector"mentioning

confidence: 99%

Calibration Procedure and Accuracy of Wind and Turbulence Measurements with Five-Hole Probes on Fixed-Wing Unmanned Aircraft in the Atmospheric Boundary Layer and Wind Turbine Wakes

et al. 2019

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For research in the atmospheric boundary layer and in the vicinity of wind turbines, the turbulent 3D wind vector can be measured from fixed-wing unmanned aerial systems (UAS) with a five-hole probe and an inertial navigation system. Since non-zero vertical wind and varying horizontal wind causes variations in the airspeed of the UAS, and since it is desirable to sample with a flexible cruising airspeed to match a broad range of operational requirements, the influence of airspeed variations on mean values and turbulence statistics is investigated. Three calibrations of the five-hole probe at three different airspeeds are applied to the data of three flight experiments. Mean values and statistical moments of second order, calculated from horizontal straight level flights are compared between flights in a stably stratified polar boundary layer and flights over complex terrain in high turbulence. Mean values are robust against airspeed variations, but the turbulent kinetic energy, variances and especially covariances, and the integral length scale are strongly influenced. Furthermore, a transect through the wake of a wind turbine and a tip vortex is analyzed, showing the instantaneous influence of the intense variations of the airspeed on the measurement of the turbulent 3D wind vector. For turbulence statistics, flux calculations, and quantitative analysis of turbine wake characteristics, an independent measurement of the true airspeed with a pitot tube and the interpolation of calibration polynomials at different Reynolds numbers of the probe's tip onto the Reynolds number during the measurement, reducing the uncertainty significantly.Atmosphere 2019, 10, 124 2 of 33 attitude, position, and velocity of the vehicle, measured by an inertial navigation system (INS), multiple coordinate transformations finally yield the wind vector. This method is widely used in manned aircraft [1,10] and on fixed-wing UAS [4][5][6][7]. The accuracy of the wind vector measurement is crucial, and the propagation of errors have many influencing factors, originating in the attitude and ground speed measurement of the aircraft, the flow angles and flow magnitude (true airspeed vector) measurement with the multi-hole probe, and also in the measurement of the thermodynamic state of the air. Extensive studies for various systems and subsystems of the wind vector measurement with manned research aircraft [11][12][13][14][15][16], including in-flight calibration procedures and uncertainty analysis [10,17], and with UAS (e.g., for the M 2 AV [7]) were performed.So far, for UAS, calibration maneuvers during flight and the influence of airspeed variations on the wind vector measurement were not addressed in terms of calibration and uncertainty analysis for the 3D wind vector measurement with multi-hole probes. Since a misalignment between the multi-hole probe's orientation and the aircraft cannot be avoided, an in-flight calibration must be applied [16]. Calibration maneuvers during flight such as the "acceleration-deceleration maneuver", the "ya...

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The Oxford Probe: an open access five-hole probe for aerodynamic measurements

Cited by 29 publications

References 8 publications

Effect of Reynolds Number on Five-Hole Probe Performance: Experimental Study of the Open-Access Oxford Probe

Effect of Reynolds Number on Five-Hole Probe Performance: Experimental Study of the Open-Access Oxford Probe

Impact of Rotor-Casing Effusion Cooling on Turbine Performance and Operating Point: An Experimental, Computational, and Theoretical Study

Calibration Procedure and Accuracy of Wind and Turbulence Measurements with Five-Hole Probes on Fixed-Wing Unmanned Aircraft in the Atmospheric Boundary Layer and Wind Turbine Wakes

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