For measurements of unsteady flow phenomena with multi-hole pressure probes, pressure transducers are integrated in the probe near the probe tip. The application of additive manufacturing enables a wide variation in probe geometries for complex use cases. The spatial characteristics of the unsteady probe are determined by the steady state calibration in a known free-jet wind tunnel. Furthermore, the acoustic/pneumatic line-cavity system, that emerges inside the channels of the probe, is investigated in detail in the temporal calibration. In order to realize multi-hole probes with higher temporal resolution, which can be operated in harsh environments, a fiber-optic pressure sensor is developed. The measurement principle of the fiber-optic sensor is based on the Fabry-Pérot interferometer effect. The sensor is operated differentially with a pressure capillary by either pressurizing the sensor or using the surrounding static pressure as the reference pressure. Besides calibration of the sensor, comparisons with a state-of-the-art piezo-resistive pressure transducer have been performed. The focus of this work is on the reproducibility of both frequency response and amplitude.

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During the calibration of an aerodynamic probe, the correlation between the present representative flow quantities of the fluid and the measurand is determined. Thus, a large number, sometimes several thousands, of different calibration points are set and measured, making this a very time-consuming process. The differences in the calibration data of similar constructed probes are very small. With the help of statistical methods, more precisely Gaussian process regressions, this similarity is exploited in order to use existing calibration data of different probes reducing the calibration time with sufficient reconstruction accuracy. Data from single-wire hot-wire probes and from five-hole probes are tested and show a very high reconstruction accuracy compared to the full calibration data set. The number of calibration points in the five-hole probe case is reduced by at least one order of magnitude with comparable reconstruction accuracy.

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An advanced unsteady multi-hole pressure probe is developed in cooperation between the Chair of Aerodynamics and Fluid Mechanics of the Technical University of Munich, the probe manufacturer Vectoflow GmbH and the sensor producer fos4X GmbH. The application of additive manufacturing enables a wide variation in probe geometries. The spatial characteristics of the unsteady probe are determined in the aerodynamic calibration in a known steady uniform jet. Furthermore, the acoustic system inside the channels of the probe is investigated experimentally in the dynamic calibration. Both aerodynamic and dynamic calibration ensure an accurate reconstruction of the velocity components. Measurements of the near wake of a circular cylinder have been recorded with the unsteady probe and compared to data from the literature and corresponding hotwire anemometry measurements. Further improvements to enhance the range of applications of the probe have been initiated: This includes the miniaturization of the probe. Moreover, an unsteady differential fiber-optic sensor and its optic and passive measurement principle are introduced which shall improve the main dynamic specifications of the probe. By combining the additive manufactured pressure probe design and the novel fiber-optic sensor, more accurate measurements of high frequency flow phenomena are expected.