Arthropods, including pollinators and pests, have high positive and negative impacts on human well-being and the economy, and there is an increasing need to monitor their activity and population growth. The monitoring of arthropod species is a time-consuming and financially demanding process. Automatic detection can be a solution to this problem. Here, we describe the setup and operation mechanism of an infrared opto-electronic sensor-ring, which can be used for both small and large arthropods. The sensor-ring consists of 16 infrared (IR) photodiodes along a semicircle in front of an infrared LED. Using 3D printing, we constructed two types of sensor-ring: one with a wider sensing field for detection of large arthropods (flying, crawling, surface-living) in the size range of 2–35 mm; and another one with a narrower sensing field for soil microarthropods in the size range of 0.1–2 mm. We examined the detection accuracy and reliability of the two types of sensor-ring in the laboratory by using particles, and dead and living arthropods at two different sensitivity levels. For the wider sensor-ring, the 95% detectability level was reached with grain particles of 0.9 mm size. This result allowed us to detect all of the macroarthropods that were applied in the tests and that might be encountered in pest management. In the case of living microarthropods with different colors and shapes, when we used the narrower sensor-ring, we achieved the 95% detectability level at 1.1 mm, 0.9 mm, and 0.5 mm in the cases of F. candida, H. nitidus, and H. aculeifer, respectively. The unique potential of arthropod-detecting sensors lies in their real-time measurement system; the data are automatically forwarded to the server, and the end-user receives pest abundance data daily or even immediately. This technological innovation will allow us to make pest management more effective.

This paper presents comparative data on the aerodynamic lift and drag of basic model representations of low-speed axial fan blade sections. Three main types of blades are investigated: flat plate, cambered plate and RAF6-E profiled airfoil. Lift and drag force are measured at three different Reynolds numbers (0.6 × 10⁵, 10⁵ and 1.4 × 10⁵) around the threshold value of 10⁵. The measurement data are compared to literature data. The aerodynamic force measurements reveal that, for Reynolds numbers below 10⁵, cambered plate blade sections can be superior to airfoil profiles in terms of aerodynamic efficiency, especially in the high-load range. The effect of leading edge bluntness is also investigated. Leaving the leading edge of cambered plates blunt, tends to be uncritical for low Reynolds numbers at angles of attack between 4° and 10° but is critical at angles between 0° and 4°.

This article presents the lift and drag coefficients of cambered plate blade sections of different relative camber at moderate Reynolds numbers. Relative cambers between 0% and 8% are investigated at an angle of attack range from 0° to 10°. Based on own measurements and literature data, empirical formulae are proposed for the determination of the lift and drag coefficients for Reynolds numbers within the range of 60,000 to 300,000. The formulae determine the lift and drag coefficients as a function of angle of attack, relative camber, and Reynolds number. Third-order polynomials have been proven to be suitable for the empirical formulae. The coefficients of the third-order polynomials have been determined and reported by the authors herein.

Empirical models capable of predicting the lift and drag coefficients of circular-arc cambered plate blades are presented, together with the detailed documentation of the related wind-tunnel techni...

The main aim of the current study is the detection of vortices in three‐dimensional fluid flow around a circular cylinder and an axial fan with the Lagrangian‐averaged vorticity deviation vortex identification method. Important parameters of the method include the size of the sought vortices and their convexity. Previous research has been conducted for the circular cylinder by the authors, however, only with respect to two‐dimensional geometries. The authors intend to compare the recommendations for the vortex detection parameters (in three dimensions) with those of the previously found results (in two dimensions). The capabilities of the LAVD technique are also tested on a practical example of a flow around an axial fan. With respect to the axial fan, the goal to be achieved is the detection and visualization of the so‐called tip leakage vortex. Comparison with the result of another detection method (Banks' vorticity predictor‐pressure corrector vortex core identification method), provided by a different author will also be performed.