A Comparison of Data-Reduction Methods for a Seven-Hole Probe
01 Jun 2002-Journal of Fluids Engineering-transactions of The Asme (American Society of Mechanical Engineers)-Vol. 124, Iss: 2, pp 523-527
About: This article is published in Journal of Fluids Engineering-transactions of The Asme.The article was published on 2002-06-01. It has received 42 citations till now. The article focuses on the topics: Interpolation & Data reduction.
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TL;DR: In this article, the authors studied the wake of a finite circular cylinder of small aspect ratio with a seven-hole probe and thermal anemometry, which was mounted normal to a ground plane and was partially immersed in a turbulent boundary layer.
Abstract: The wake of a finite circular cylinder of small aspect ratio was studied with a seven-hole probe and thermal anemometry. The cylinder was mounted normal to a ground plane and was partially immersed in a turbulent boundary layer. The time-averaged velocity and streamwise vorticity fields showed the development of the tip vortex structures, the extent of the near-wake recirculation zone, the downwash phenomenon and base vortex structures within the boundary layer. The wake structure and power spectra were similar for cylinder aspect ratios of 5 to 9, but a distinctly different behaviour was observed for an aspect ratio of 3.
296 citations
Cites methods from "A Comparison of Data-Reduction Meth..."
...Based on the recommendations of Sumner (2002) , the calibration grid spacing was 8.1� , the angular range of the calibration was ±72.9� and the direct interpolation data-reduction method of Zilliac (1989) was adopted....
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...Wake measurements were made with a seven-hole pressure probe (3.45-mm diameter, 30� cone angle) that was manufactured at the University of Saskatchewan ( Sumner 2002 )....
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California Institute of Technology1, École centrale de Lyon2, Michigan State University3, Delft University of Technology4, Technische Universität Darmstadt5, Langley Research Center6, German Aerospace Center7, City University of New York8, University of Michigan9, Northrop Grumman Corporation10, University of Maryland, College Park11, University of Montenegro12, University of Notre Dame13, University of Utah14, Technical University of Madrid15
58 citations
TL;DR: In this article, the tip vortex structures near the free end of a circular cylinder of diameter D and height L were studied experimentally at a Reynolds number Re D =6×10 4.
55 citations
TL;DR: In this article, the time-averaged velocity and streamwise vorticity fields within the wake of a short stack were investigated in a low-speed wind tunnel using a seven-hole pressure probe.
33 citations
Cites background or methods from "A Comparison of Data-Reduction Meth..."
...The probe was calibrated in situ using an automated variable-angle calibrator, with a calibration grid spacing of 8:1 i over a flow angle range of ˙72:9 i . A direct-interpolation calibration data-reduction method was used [ 10 ]....
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...indicates that the local flow angle exceeded the angular range of the seven-hole probe, which was estimated at ˙70 i [ 10 , 11]....
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TL;DR: In this article, the effect of a wake-mounted splitter plate on the flow around a surface-mounted finite-height square prism was investigated experimentally in a low-speed wind tunnel.
31 citations
References
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TL;DR: A method of blvariate interpolation and smooth surface fitting is developed for z values given at points irregularly distributed in the x-y plane for Bivariate Interpolation and Smooth Surface Fitting for Irregularly Distributed Data Points.
Abstract: A method of blvariate interpolation and smooth surface fitting is developed for z values given at points irregularly distributed in the x-y plane. The interpolating function is a fifth-degree polynomial in x and y defined in each triangular cell whmh has projections of three data points in the x-y plane as its vertexes. Each polynomial is determined by the given values of z and estimated values of partial derivatives at the vertexes of the triangle. Procedures for dividing the x-y plane into a number of triangles, for estimating partial derivatives at each data point, and for determining the polynomial in each triangle are described A simple example of the application of the proposed method is shown. Key W6rds and Phrases bivariate interpolation, interpolation, partial derivative, polynomial, smooth surface fitting CR Categories: 5.13 The Algorithm Bivariate Interpolation and Smooth Surface Fitting for Irregularly Distributed Data Points ACM Trans. Math. Software 2, 1(June 1978), 160-164.
732 citations
01 Feb 1997
TL;DR: In this paper, the roll-up of a wingtip vortex, at Reynolds number based on chord of 4.6 million, was studied with an emphasis on suction side and near wake measurements.
Abstract: The roll-up of a wingtip vortex, at Reynolds number based on chord of 4.6 million was studied with an emphasis on suction side and near wake measurements. The research was conducted in a 32 in. x 48 in. low-speed wind tunnel. The half-wing model had a semi-span of 36 in. a chord of 48 in. and a rounded tip. Seven-hole pressure probe measurements of the velocity field surrounding the wingtip showed that a large axial velocity of up to 1.77 U(sub infinity) developed in the vortex core. This level of axial velocity has not been previously measured. Triple-wire probes have been used to measure all components of the Reynolds stress tensor. It was determined from correlation measurements that meandering of the vortex was small and did not appreciably contribute to the turbulence measurements. The flow was found to be turbulent in the near-field (as high as 24 percent RMS w - velocity on the edge of the core) and the turbulence decayed quickly with streamwise distance because of the nearly solid body rotation of the vortex core mean flow. A streamwise variation of the location of peak levels of turbulence, relative to the core centerline, was also found. Close to the trailing edge of the wing, the peak shear stress levels were found at the edge of the vortex core, whereas in the most downstream wake planes they occurred at a radius roughly equal to one-third of the vortex core radius. The Reynolds shear stresses were not aligned with the mean strain rate, indicating that an isotropic-eddy-viscosity based prediction method cannot accurately model the turbulence in the cortex. In cylindrical coordinates, with the origin at the vortex centerline, the radial normal stress was found to be larger than the circumferential.
270 citations
TL;DR: The rollup of a wingtip vortex, at a Reynoldsnumber based on chord of 4.6 £ 10 6, was studied with an emphasis on SUctionside and very near-wakemeasurements (upto x/c = 0.678 downstreamofthetrailingedge) as mentioned in this paper.
Abstract: The rollup of a wingtip vortex, at a Reynoldsnumber based on chord of 4 .6 £ 10 6 , was studied with an emphasis onsuctionsideandverynear-wakemeasurements(upto x/c = 0.678 downstreamofthetrailingedge).Theresearch was conducted in a 32 £ 48 in. (0.81 £ 1.22 m), low-speed wind tunnel. The rectangular half-wing model had a semispan of 36 in. (0.91 m), a chord of 48 in. (1.22 m), and a rounded tip. Seven-hole pressure probe measurements of the velocity ® eld surrounding the wingtip showed that a large axial velocity up to 1.77 U 1 developed in the vortex core. This high a level of core axial velocity has not been measured previously. Triple-wire probes were used to measure all components of the Reynolds stress tensor. It was determined from correlation measurements that
244 citations
TL;DR: This monograph can serve as a useful sequel to the monograph by Bryer and Pankhurst, entitled “Pressure-probe Methods for Determining Wind Speed and Flow Direction”, adding further details on topics discussed therein and other topics not already included.
204 citations
TL;DR: In this paper, the calibration of a non-nulling, conical, seven-hole pressure probe over a large range of flow onset angles is described, and the calibration procedure is based on the use of differential pressures to determine the three components of velocity.
Abstract: This report describes the calibration of a non-nulling, conical, seven-hole pressure probe over a large range of flow onset angles. The calibration procedure is based on the use of differential pressures to determine the three components of velocity. The method allows determination of the flow angle and velocity magnitude to within an average error of 1.0° and 1.0% respectively. Greater accuracy can be achieved by using high quality pressure transducers. Also included is an examination of the factors which limit the use of the probe, a description of the measurement chain, an error analysis, and a typical experimental result. In addition, a new general analytical model of pressure probe behavior is described and the validity of the model is demonstrated by comparing it with experimentally measured calibration data for a three-hole yaw meter and a sevenhole probe.
91 citations