**4. Conclusions**

The article presents the concept of a method of correction of the dynamic measurement error of tachometric anemometers. The results of the pilot studies carried out for the vane anemometer confirmed the adopted assumptions and the effectiveness of the method.

Measurements of velocities fluctuations using tachometric anemometers are disturbed by a dynamic error, and the measured average velocity is overestimated. However, it is possible to correct these errors by processing the output signal. The correction algorithm based on the dynamic model of the anemometer enables the extension of the frequency bandwidth and reduction in the dynamic error. The algorithm requires measuring the angular velocity of the rotor with high accuracy and time resolution, and calculating the derivative of the angular velocity. The calculated derivative of the angular velocity of the rotor is used for the measurement correction. The quality of the estimation of this quantity affects the effectiveness of the method. It is important to optimize the derivative calculation algorithm to minimize the dynamic error, but also the noise of the measurement signal.

It is not a trivial issue to create a reference flow for testing the dynamic properties of anemometers. For the purposes of the research presented in this article, a rotating diaphragm modulating the air stream was used. To control the test flow, a Constant-Temperature Anemometer with a hot-wire sensor having a diameter of 5 μm was used. The tests showed a significant reduction in the dynamic error and the extension of the frequency bandwidth of the vane anemometer by about 40 times for the velocity of 2.5 m/s, and 10 times for the velocity of 12.5 m/s. The quantitative parameters of the improvement in the

dynamic properties of the measurement are mainly related to the quality of the estimation of the derivative of the angular velocity of the rotor. The presented method and its possible variants can improve the dynamic parameters of tachometric anemometers used in the measurement of fast-changing flows. This requires the use of a high-performance angular velocity sensor and signal processing system in these anemometers.

The article concerns only one selected problem in the field of tachometric anemometers. It proposes an original method of minimizing the dynamic error in the measurement of flows that vary in time. The issues related to mechanical anemometers vary and cannot be discussed in detail in the case of the pilot verification tests presented here. Issues such as total measurement uncertainty, directional characteristics of the anemometer, influence of the medium parameters on the measurement, invasiveness of the sensor, and many others are considered in other articles on measurements with mechanical anemometers. The article is a preliminary conceptual work and presents pilot research confirming the assumptions of the method. The implementation of the presented method in actual, commercial measuring instruments intended for laboratory, technical and industrial tests [35] requires taking into account individual metrological requirements and parameters of the anemometer. These works should take into account the parameters of the tested flow, the required metrological properties, the type, structure and parameters of the rotor, and other individual features.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Data available via the author's email.

**Conflicts of Interest:** The author declare no conflict of interest.
