In the modern conditions, energy efficiency is one of the most important world problems. One of the important factors influencing the overall energy efficiency of buildings is air distribution in rooms. Literature review shows different options of efficiency estimation of air exchange with significant limitations. Some of them have non-obvious physical meaning. Certain of them do not take into account possible room zoning. Consideration of turbulence intensity in the efficiency estimation was not found. In this work, we propose an approach to estimate the air exchange efficiency in different kind of rooms. It is a relation of minimum room demands and inlet air potentials. Additional definitions are introduced for the parameters and demands estimation. The mechanical energy of the air is used for the estimation, which includes the energy of averaged motion and turbulent pulsation. Special approach is offered for turbulence intensity computation for energy calculations. The example of efficiency estimation of air exchange in a museum room with constant air volume system of air conditioning is solved.

Rain gardens are used to solve urban problems related to the negative impact of stormwater. (1) Scientific contributions from different countries provide general guidelines for the design and operation of rain gardens in different geographical areas. Given the small spatial scale of rain gardens, the use of existing infiltration models often leads to design errors. (2) The purpose of this paper is to develop a hydrological model by introducing a system of equations that extends the ability to calculate the rate, flow rate and time of saturation of layers with moisture and rainwater leakage from the rain garden system. (3) The results obtained allow us to describe the dynamic processes of passage and saturation of layers of the rain garden at a certain point in time, which extends the ability to calculate the flow rate. It was established that the smaller the area of the rain garden compared to the area of the catchment basin, the faster it reaches its full saturation. Increasing the thickness of the rain garden layers allows for an increase in the efficiency of water retention at a lower value of the area ratio. (4) The practical significance of the results obtained is especially important for the correct description of hydrodynamics in the system and determining the optimal conditions for the effective functioning and management of the rain garden structure for any climatic region.

A simplified approach for estimation of turbulence intensity of turbulent submerged wall jets on cylindrical surfaces with different curvature is shown. It is a continuation of researches, performed by professor of Kyiv National University of Construction and Architecture Andrei Tkachuk. By using the geometric and kinematic analysis of turbulent macrostructure, it is proposed to found not only averaged flow characteristics but also turbulent pulsations. Analysis of visual researches of submerged jets in different works allows assuming such kind of flow as touching large round vortices (puffs), which roll by free flow boundary. In this work, geometric and kinematic analysis of this macrostructure chart in concave submerged wall jets is performed, and turbulence intensity is found. Results of the same analysis for submerged convex wall jets allow obtaining common dependencies for different curvature. The results are accepted by comparison with known experimental data.

Rainwater management is one of the important problems of cities. At very strong downpours, storm sewer systems may not capture the rainwater, which floods pavements and roadways. The water flushes fuel and oil traces after vehicles, fallen debris, and other pollutants, which will be moved to the ground, ponds, rivers, seas, etc. In past, the problems were solved using engineering approaches – a set of rainwater receivers, a duct network, and at best, wastewater treatment plants. Now, the sponge city concept is a better solution that uses a biotechnological way for throttling water flows, drainage, and purifying them. The work aims to improve the design of roads to fully absorb rainwater from them with maximum convenience for road users. We propose a design of roads using special “green structures” – rain-garden bands along the sides of roadways. We tested its ability of water capturing on the example of Kyiv city by matching the ability with the strongest precipitation observed. In addition, the proposed plants can extinguish the energy of bouncing cars during road accidents for the protection of pavements.

European Norms for ventilation contain turbulence intensity requirements in rooms. One of the determining factors is turbulence intensity in ventilation jets. We found an approach for geometric analysis of turbulent macrostructure for subsonic flows with large-scale vorticity i.e. ventilation jets and boundary layers between flows. This approach requires building of simplified turbulent macrostructure chart and performing geometrical analysis of it. In previous works, using the approach we analytically found averaged characteristic of free jets, jets in flows and jets laid on different shape surfaces without requirements of any experimental data. The results of geometrical analysis of heat transfer between flows are used in Ukrainian norms. In this work we found turbulence intensity of wall jets on flat surfaces such as room walls or ceiling without any experimental values. The results coincide with known experimental data and may be used in flow calculation in rooms.