A method of calibration of a seven-hole pressure probe for measuring highly three-dimensional flows

A novel method for extending the calibration range of five-hole probe for highly three-dimensional flows

Abstract: Five-hole probe used in a non-nulling manner to find unknown flow properties is limited to a low range of acceptance angles due to singularity encountered in the calibration procedure. A novel method to extend this range by avoiding singularity is developed allowing calibration of a five-hole probe up to much larger angles of pitch and yaw. The method has been tested using experimental calibration data of a five-hole probe that were obtained employing the 18 in. ×18 in. subsonic closed circuit wind tunnel of the University of New South Wales at the wind tunnel speed of 15 m/s. The new procedure shows that the calibration range can be successfully extended to angles of up to ±75°. A step-by-step procedure of using the new technique is also detailed in this chapter.

Development of a functional relationship between port pressures and flow properties for the calibration and application of multihole probes to highly three-dimensional flows

Abstract: It is common in the calibration of multihole probes to curve-fit the calibration data in order to determine a relationship between measured port pressures and flow properties. The parameters used in these techniques typically lack a theoretical background. In this article, a functional relationship is developed, based on theoretical considerations, that relates the port pressure directly to the flow properties and details a procedure that enables flow properties to be determined from the measured pressures of the multihole probe. The method is simple, easy to implement and provides a better understanding of the multihole probe operation in a three-dimensional flow.

Examining the Effect of Flow Reversal on Seven-Hole Probe Measurements

Abstract: Multihole pressure probes are frequently used to gather e ow data, sometimes in highly three-dimensional e ow. If the e ow is reversed, no method currently exists for determining whether the multihole probe is facing the right direction for data acquisition, and that the e ow is as such. A seven-hole probe is rotated in yaw by 360 deg, and rules are formulated to determine if a seven-hole probe is in a reversed e ow. The current study allows seven-hole probes to be used for gathering data in steady reversed e ows and gives an indication whether a pressure probe is insufe cient for the measurement instrument, as in the case of highly recirculating unsteady turbulent e ows. An application of the technique thus developed is also given.

Seven-hole cone probes for high angle flow measurement Theory and calibration

Abstract: A non-nulling seven-hole conical pressure probe capable of measuring flow conditions at angles up to 75 deg relative to its axis is described. The theoretical rationale of the seven-hole probe is developed and the calibration procedure outlined. Three-variable third-order polynomial functions are used to represent local values of relative flow angles, total pressure, and total minus static pressure. These flow properties are determined explicitly from measured probe pressures. Flow angles are determined within 2.5 deg and Mach number within 0.05 with 95% certainty. The probe can be used in subsonic compressible and incompressible flows.

Modified calibration technique of a five-hole probe for high flow angles

Abstract: A new method is described for calibrating a five-hole probe for extending the useful measurement range up to flow angularities of 85°. The calibration method involves adjustment of the calibration coefficients to allow valid calibration at larger flow angles. The extended range calibration curves for flow angularity, total and static pressures are presented. The present range is valid in pitch only when the yaw ports are nulled.

Seven hole probe measurement of leading edge vortex flows

Abstract: This paper discusses the use of a seven-hole probe on measurements of leading edge vortices of highly sweep delta wing planforms. Intrusive probe data taken with the pressure probe were compared with nonintrusive measurements made with laser Doppler anemometry system. In addition to probe size, the natural position of breakdown and the sweep angle of the wing are also factors in determining sensitivity of the flow to probe interference. At low angles of attach vortex breakdown does not occur in the vicinity of the model and the seven hole probe was found to yield reasonably accurate measurements. When the angle of attack of the model was increased so that vortex breakdown was near the trailing edge, introducing the probe over the wing would cause the breakdown position to move ahead of the probe. However, when breakdown naturally occurred ahead of the mid-chord of the wing the vortices were found to be less sensitive to a probe placed behind the breakdown point. Vortex breakdown on a lower swept wing is found to be more sensitive to interference. Near the breakdown region, seven hole probe measurement is less accurate due to a combination of probe interference and flow reversal.