The results of an experimental study of the flow structure in the near zone of an annular swirling jet are presented. The data were obtained using a two-component laser-Doppler anemometer for the annular jets with a swirl angle of 0–60°. The results of measurements of the average velocity and pulsations in the near jet region (up to 5 diameters of the outer ring) are presented. Based on the analysis performed, it is shown that formation of an internal toroidal vortex near the nozzle plays an important role in the flow dynamics and the process of annular jet mixing. Formation of a stationary toroidal vortex outside the ring is also noted. These structures determine the flow in the near zone of the jet. With the studied Reynolds numbers, this character of the flow in the near zone leads to an increase in the mixing rate, high degree of turbulence, and an increase in the jet ejection capacity.

The results of experimental study of interaction in a system of two turbulent circular parallel jets are presented. The studies were conducted using a two-component laser-Doppler anemometer with an adaptive time selection of the velocity vector. The distance between the jet axes in experiments was varied within s/D = 1.8-3.0 with Reynolds numbers Re = 5500 and 11000. Distributions of average and pulsating components of the velocity vector at distances from the nozzle H/D = 0-10 were obtained. These distributions were analyzed in the region closest to the nozzles and the region of the greatest jet interaction.

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The article presents an experimental study of the turbulent flow in matrix channels. Using the modern optical contactless laser Doppler anemometer (LDA) method, an idea of the turbulent three-dimensional flow inside the cells of matrix channels is developed. The results of the study of the matrix channel show that the so-called vortex matrix effect is not formed. The most important factor that causes a high degree of heat transfer from the walls is the intense spiral motion between the matrix cells. The measurements also show that the effects associated with the lateral boundaries of the channel play a significant role. Based on the assumption of the decisive role of the spiral flow between the cells of the matrix channel, a formula for the integral pressure loss is proposed.