The influence of the probe size and geometry on the quality of fast-response measurements in turbomachines has been experimentally investigated. For investigations in the static domain (time-independent flows) probes were calibrated in two continuously operating wind tunnels in the range 0.2 < M < 1.2. For dynamic calibrations in time-variant flows model experiments in water (0.025 < k < 0.4, reduced frequency) were performed. Aerodynamic characteristics were determined for a great number of probe geometries, such as circular cylinders and wedge-type probes with varied apex angles, locations of the sensing holes, and leading edge shapes. The experiments comprised investigations in tolerance ranges for prismatic total pressure probes, yaw angle sensitivity, yaw angle, and Mach number effects on calibration and influence of dynamic yaw angle fluctuation on probe characteristics. As a result of the experiments errors due to static and dynamic aerodynamic effects could be quantified. The majority of the errors arising during measurements in turbomachines can be directly related to the probe size. An important number of these errors are systematic and can be analytically modeled and hence their influence corrected. In fluctuating flows the most severe measurement errors, which often may exceed the quantity of interest, are due to dynamic stall effects. This phenomenon, which is of transient nature and cannot be corrected, is typical for sharp wedge probes, but is not present with circular cylinders, and the effects are much smaller with very blunt wedges.

Issue Section:
Research Papers
Topics:
Design, Probes, Errors, Flow (Dynamics), Wedges, Yaw, Calibration, Circular cylinders, Turbomachinery, Pressure, Geometry, Mach number, Shapes, Transients (Dynamics), Water, Wind tunnels
1.
Ainsworth, R. W., and Strickland, A. D., 1992, “Experimenting With Fast-Response Aerodynamic Probe Geometries,” Proceedings of the 11th Symposium on Measuring Techniques for Transonic and Supersonic Flows in Cascades and Turbomachines, Munich, Germany.
2.
Beddoes, T. S., 1980, “A Qualitative Discussion of Dynamic Stall,” AGARD-R-679 Special Course on Unsteady Aerodynamics.
3.
Browne, L. W. B., Antonia, R. A., and Chua, L. P., 1989, “Velocity Vector Cone Angle in Turbulent Flows,” Experiments in Fluids, Vol. 5.
4.
Bryer, D. W., and Pankhurst, R. C., 1977, “Pressure Probes for Determining Wind Speed and Flow Direction,” National Physical Laboratory, Her Majesty’s Stationery Office, United Kingdom.
5.
Carr, L. W., McAllister, K. W., and McCroskey, W. J., 1976, “Dynamic Stall Experiments on Oscillating Airfoils,” AIAA Journal, Vol. 14, No. 1.
6.
Cook, S. C., 1989, “The Development of a High Response Aerodynamic Wedge Probe and Use on a High-Speed Research Compressor,” ISABE 89-7118.
7.
Gossweiler, C., Herter, D., and Kupferschmied, P., 1992, “Fast-Response Probe Measurements in a Turbulent Pipe Flow,” Proceedings of the 11th Symposium on Measuring Techniques for Transonic and Supersonic Flows in Cascades and Turbomachines, Munich, Germany.
8.
Humm, H. J., and Verdegaal, J. I., 1992, “Aerodynamic Design Criteria for Fast-Response Probes,” Proceedings of the 11th Symposium on Measuring Techniques for Transonic and Supersonic Flows in Cascades and Turbomachines, Munich, Germany.
9.
Humm, H. J., and Verdegaal, J. I., 1993, “Investigation of the Influence of Velocity Gradients on Measurements With a Wedge Probe,” Technical Note 92-06, Swiss Federal Institute of Technology, Turbomachinery Laboratory [in German].
10.
Humm, H. J., 1994, “On Aerodynamic Design Criteria for Fast-Response Probes,” PhD Thesis, Swiss Federal Institute of Technology, Turbomachinery Laboratory [in German].
11.
Kovasznay, L. S. G., Tani, I., Kawamura, M., and Fujita, H., 1981, “Instantaneous Pressure Distribution Around a Sphere in Unsteady Flow,” ASME Journal of Fluids Engineering, Vol. 103.
12.
Kupferschmied, P., and Gossweiler, C., 1992, “Calibration, Modelling and Data Evaluation Procedures for Aerodynamic Multihole Pressure Probes on the Example of a Four Hole Probe,” Proceedings of the 11th Symposium on Measuring Techniques for Transonic and Supersonic Flows in Cascades and Turbomachines, Munich, Germany.
13.
Kupferschmied, P., and Ribi, B., 1987, “Calibration of Pneumatic 4-Hole Probes for Pressure and Velocity Measurements in Inhomogenuous Flow Fields,” Diploma work, Swiss Federal Institute of Technology, Turbomachinery Laboratory [in German].
14.
McCroskey, W. J., 1977, “Some Current Research in Unsteady Fluid Dynamics—The Freeman Scholar Lecture,” ASME Journal of Fluids Engineering, Vol. 99.
15.
Telionis, D. P., 1981, Unsteady Viscous Flow, Springer.
16.
Wyler, J. S., 1975, “Probe Blockage Effects in Free Jets and Closed Tunnels,” ASME Journal of Engineering for Power, Vol. 97, Oct.
This content is only available via PDF.
Copyright © 1995
 by The American Society of Mechanical Engineers
You do not currently have access to this content.