Results of the theoretical and experimental investigations of the turbulent mean swirl flows characteristics change along straight conical diffuser of incompressible fluid (air) are presented in this paper. The main swirl flow characteristics review is given. In addition: the specific swirl flow energy, the energy loss, the mean circulation, the swirl flow parameter, the ratio between the swirl and axial flow loss coefficients change along the diffuser are presented. Among other values: the Boussinesq number, outlet Coriolis coefficient and swirl flow loss coefficient dependences on inlet swirl flow parameter are also given. The swirl flow specific energy and outlet Coriolis coefficient calculation procedure are presented in this paper, as well as experimental test bed and measuring procedures. The swirl flow fields were induced by the axial fan impeller. Various swirl parameters were achieved by the impeller openings and rotational speeds.

The zebrafish is a robust model for studying human ophthalmic function and disease because of its fecundity, life-cycle, and similarities between its retinal structure and the human retina. Here, we demonstrate longitudinal in vivo imaging of retinal structure using optical coherence tomography (OCT) and noninvasive retinal vascular perfusion imaging using OCT angiography (OCT-A) in zebrafish. In addition, we present methods for retinal vascular segmentation and biometry to quantify vessel branch length, curvature, and angle. We further motivate retinal vascular biometry as a novel method for noninvasive zebrafish identification and demonstrated 99.9% accuracy for uniquely identifying eyes from a set of 200 longitudinal OCT/OCT-A volumes. The described methods enable the quantitative analysis of the vascular changes in zebrafish models of ophthalmic diseases and may broadly benefit large-scale zebrafish studies.

The determination of the energy characteristics of a double-regulated hydro turbine is based on numerous measuring points during extensive and expensive experimental model tests in the laboratory and on site prototype tests at the hydropower plant. By the spatial interpolation of representative measured points that belong to the so-called on-cam curves for different speed factors, the hill performance diagram is obtained. The focus of the paper is the contemporary method of artificial neural network models use for the prediction of turbine characteristics, especially in not measured operation modes. A part of the existing set of experimental data for the Kaplan turbine energy parameters is used to train three developed neural network models. The reliability of applied method is considered by analysing, testing and validating the predicted turbine energy parameters in comparison with the remaining data.

Hydraulic transients analyses are necessary during the design stage of both new and refurbished hydropower plants (HPPs). In this paper, transients of specified most extreme operational regimes are investigated for a long derivation system, provided with a surge tank as well as pressure relief valves (PRVs) at the turbines spiral casing. The transients analyses are focused on water-mass oscillations and water hammer. Investigations for various exploitation regimes and different operating laws of the PRV's are adopted. Results are obtained by means of an original software developed for these analyses. The model was duly calibrated, and the results were compared with the results of the transient analyses from the original design phase of the existing HPP.