• Journal of the Korean Society for Aviation and Aeronautics
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• v.14 no.1
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• pp.43-48
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• 2006

The present study was carried out in order to develope a seven-hole pressure probe which is able to measure high flow angles. The seven-hole pressure probe is a non-nulling, directional velocity probe used for measuring three dimensional flow that having high flow angles. A 4 mm diameter seven-hole conical pressure probe was manufactured with a cone angle of 70$^{\circ}$. The probe was comprised of seven 1 mm diameter stainless steel tubes packed close together and fitted into an outer stainless steel sleeve. The calibration procedure is based on the use of the Callington's polynomial curve-fit method. The validity of the seven-hole conical pressure probe is demonstrated by comparisons with hot-wire data.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.11
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• pp.1437-1448
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• 1997

Pressures of a five-hole probe were measured for a full range of yaw and pitch angles and complete pressure coefficient maps were obtained. Based on these maps, various features of five-hole probe pressures were revealed and new five-hole probe calibration coefficients were devised. The new calibration coefficients show non-diverging characteristics for any flow direction and one-to-one correspondence for a wide range of flow angles. These calibration coefficients expand the valid flow angle range of five-hole probe calibration by .+-.10 degrees and complement a critical defect of five-hole probe zone-division calibration method which has not been known yet. Moreover new non-diverging calibration coefficients have advantages in nulling methods, too.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.5
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• pp.637-649
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• 1997

Effects of cone angle, pressure-hole orientation and Reynolds number on the five-hole probe calibration have been investigated for eight large-scale conical five-hole probes, which have either perpendicular pressure holes or forward-facing pressure holes for the cone angles of 45 deg, 60 deg, 75 deg and 90.deg. Pitch and yaw angles are changed from -40 deg to +40 deg with an interval of 5 deg, respectively, when the probe Reynolds numbers are 1.77*10$^{4}$, 3.53*10$^{4}$ and 7.06*10$^{4}$. The result shows that larger cone angle results in more sensitive changes in the calibration coefficients. In the case that the cone angle is 45 deg, the pitch-angle and yaw-angle coefficients of the five-hole probe with the perpendicular pressure holes show a very different trend compared with those of the five-hole probe with the forward-facing pressure holes. On the other hand, when the cone angle is more than 60 deg, each calibration coefficient is nearly independent of the pressure-hole orientation. Additionally, the effects of the Reynolds number on the calibration coefficients are also reported in detail.

• Journal of the Korean Society of Visualization
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• v.18 no.3
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• pp.122-128
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• 2020

In the field of experimental fluid dynamics, the 5-hole probe is one of the most widely used tools to measure flow velocity and pressure. We hereby describe the development of an inexpensive laboratory-based flow calibration system for 5-hole probes. The system is applied to a custom L-shaped probe, and the probe performance is compared against a standard commercial probe in a custom wind tunnel. The setup allows rotation of the probe around the yaw and pitch axes. Static and total pressure values are calculated, and then calibration maps are constructed based on the yaw and pitch angles. Using these maps, errors of the custom probe are found to be ±5% for velocity magnitude and ±3° for direction, compared to the commercial probe, when both pitch and yaw angles are within 40°.

• The KSFM Journal of Fluid Machinery
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• v.13 no.6
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• pp.5-12
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• 2010

Comparative study on the flow measurement by 5-hole and 7-hole probes was conducted in a linear cascade with tip clearances of 2.3%, 3.1%, and 4.4% of the blade span. Calibration range of the 5-hole and the 7-hole probes were ${\pm}25$ and ${\pm}50$ degrees, respectively. Results show that the secondary flow and total pressure loss measured by the 5e-hole and 7-hole probes were similar at small tip clearance cases. However, at the tip clearance of 3.1% and 4.4% of the blade span cases, flow angles exceeding the calibration range of the 5-hole probe were observed. Because of the wider calibration range, larger flow angle by strong leakage vortex could be measured by the 7-hole probe.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.1125-1132
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• 2009

The theory and a probe of the pilot hole wall deformation method, which is a 3-dimensional stress measurement method based on the stress relief principle, were developed. A pilot hole is drilled from the bottom of a borehole and the stress measurement probe is inserted into the pilot hole. The borehole is advanced as the overcoring and the changes in the radius of the pilot hole in three directions and in the axial lengths between the borehole bottom and the pilot hole wall along four axial lines are measured by cantilever type-displacement sensors. The differences between the displacements by the elastic stress analysis and those measured by using the probe were within 3% in the uniaxial compression test of an acrylic resin plate having a hole.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.96.5-96
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• 2001

The probe with a 110mm diameter is originated and fabricated to measure hole accuracies of extremely deepholes. It consists of a measuring unit, an actuator unit, an active rotation stopper and a feed unit. The rolling of the probe is restricted and adjusted by the active rotation stopper. The probe is fed by the feed unit. In this measurement, accuracies are measured by using a rolling proof apparatus and machine table of deep hole boring machine instead of the stopper and the feed unit, respectively. Straightness, roundness and a diameter of a 110-mm hole are measured by the probe and testers made for each measuring purpose ...

• Journal of Power System Engineering
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• v.18 no.1
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• pp.22-31
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• 2014

This paper introduced the new calibration algorithm of a straight-type five-hole pressure probe necessary for calculating three-dimensional flow velocity components. The new velocity data reduction method using both a commercial two-dimensional curve-fitting program and the zone partition method of a calibration map was firstly introduced in this study. This new calibration method can be applied up to the wide flow angle of ${\pm}80^{\circ}$ despite of using a five-hole pressure probe because this data reduction method showed a comparatively good performance in calculating yaw and pitch angles from the calibration map.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.445-456
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• 2005

The research concentrates on improving the in-hole seismic probe, which has been developed in past five years, to be used in stiffness measurements of tunnel-face materials. The probe was down-sized to be fit in 45-mm diameter holes(or BX) drilled by a jumbo-drill, which is used to drill holes to install explosives for tunneling. Also trigger system was improved by using a down-speeding motor for operating convenience and air packing system was replaced with a set of plate-springs to eliminate supply of compressed air. These modifications are to adjust the probe for the unfavourable environment inside of tunnels and to test without any further drilling cost. The probe and testing procedure were successfully adopted with horizontal holes drilled by a jumbo-drill at a tunnel-face to evaluate the stiffness of rock mass. The measured shear wave velocities can be used to estimate deformation properties of rock mass for tunnel analyses.

• Journal of the Korean Geotechnical Society
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• v.21 no.1
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• pp.105-114
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• 2005

An in-hole seismic method, which has been developed for measuring dynamic properties of subsurface materials, was improved in terms of cost effectiveness and practicality. The upgraded features include the motorized triggering system rather than the manual prototype version in the previous studies and a connecting rod between source and receiver in the module. The probe, thus, can be used for the field measurements of soil properties as well as those of rocks. The performance of the probe has been evaluated through extensive cross-hole tests and in-hole tests at various sites.