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The spread of the novel coronavirus disease (COVID-19) continues to show that geographic barriers alone cannot contain the virus. Asymptomatic carriers play a critical role in the nature of this virus, which is rapidly escalating into a global pandemic. Asymptomatic carriers can inadvertently transmit the virus through the air stream. Many diseases can infect human bodies with tiny droplets or particles that carry various viruses and bacteria that are generated by the respiratory system of infected patients. This article presents the numerical results of the spread of droplets or particles in a room. The proposed numerical model in this work takes into account the sedimentation of particles or droplets under the action of gravitational sedimentation and transport in the room during the process of breathing and sneezing or coughing. Three different cases are numerically investigated taking into account normal breathing and coughing or sneezing, respectively, and three different rates of particle ejection from the mouth are considered. Navier–Stokes equations for incompressible flows were used to describe three-dimensional air flow inside ventilated rooms. The influence of ventilation rate on social distancing is also computationally investigated. It was found that particles can move up to 5 m with a decrease in concentration in the direction of the air flow. The conclusions made in this work show that, given the environmental conditions, the two meter social distance recommended by WHO is insufficient.

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In this paper, was presented the numerical simulation of air pollution by particles with different sizes from the Ekibastuz State district power plant-1 (Ekibastuz SDPP-1), which is located on the northern side of Zhyngyldy Lakeshore, the Republic of Kazakhstan in real scales using the three-dimensional mathematical model. It was found that the deterioration of the environment is due to the release of a large amount of SOx, NOx and the volatile particles of Suspended Particulate Matter and Respirable Suspended Particles matter (SPM and RSPM), which cause human and animal diseases. For the adequacy of the mathematical model, the test problem was solved. The experimental data were used to evaluate the applicability of the mathematical model and the numerical algorithm for the test problem. The obtained numerical simulation results are in good agreement with the numerical results of other authors and the experimental data. In addition, to select the optimal turbulent model, the obtained simulation results for different turbulent models were compared with experimental data. Moreover also the boundary conditions for turbulent models (k − ε, k − ω), boundary conditions for turbulent kinetic energy were chosen to match the experimental data.

In this paper, obtained numerical results of the thermal pollution from the operation of a power plant are presented when using the Irtysh River as a natural water cooling system. A two-dimensional formulation by using the "shallow water" approximation is often used as a numerical solution of such problems. For two-dimensional numerical modeling, it is possible to determine the floating flow together with its characteristics of mixing heated water discharge from lateral projections to transverse flow. Furthermore, data from the experiment and numerical values of other authors were used in order to check the conformity of the computational results. The obtained numerical values gave good agreement comparing with data from the experiment, specially the jets trajectory, the recirculation zones size and the dimensionless excess temperature distribution. The obtained data as a result of numerical simulation can be used to study problems associated with the mixing of heated water discharged from the lateral direction into the transverse flow. Also these studies were conducted to study thermal contamination under different scenarios, the impact of heated water discharge from a power plant in the Irtysh River, and the areas of thermal pollution for different velocity scenarios were determined. ARTICLE HISTORY KEYWORDS Navier-Stokes equation;operational capacities of the power plant; finite volume method; the SIMPLE algorithm; thermal discharge; heat exchange