Numerical simulations of two-phase flow induced fluctuating forces at a pipe bend have been carried out to study the characteristics of multiphase flow induced vibration (FIV). The multiphase flow patterns and turbulence were modelled using the volume of fluid (VOF) method and the − turbulence model respectively. Simulations of seventeen cases of slug and churn flows have been carried out showing the effects of superficial gas and superficial liquid velocities. The simulations results show good agreement of the volume fraction fluctuation frequencies of slug and churn flows with the reported experiment. In addition, the vibration characteristics of the excitation force have been accurately captured. The simulation results show that the predominant frequency of fluctuations of force decreases and the RMS of force fluctuation increases with the increase of superficial gas velocity. On the other hand, both predominant frequency and the RMS of force fluctuations increases with the increase of superficial liquid velocity. Increase of gas fraction narrows the range of frequency ranges, while increasing the liquid expands the frequency ranges of force fluctuations.

Purpose: The purpose of the study is to investigate the dispersion of droplet nuclei/aerosol which are produced during coughing and continuous talking in order to quantify the risk of infection due to airborne disease transmission. Methods: A three-dimensional modelling of aerosol transport due to human respiratory activities such as coughing and talking within a room environment has been simulated using CFD technique. An inert scalar transport equation was used to represent aerosol cloud, while turbulence was modelled with the \(k-ϵ\) turbulence model. A modified Wells-Riley equation was used to calculate the risk of infection based on quanta emission concept. Results The spatial and temporal distribution of aerosol cloud within the room is initially driven by the upward flowing thermal plume surrounding the human, but later driven by the flow field constrained by the walls and cooler air movement. While the cough generated aerosols are concentrated in a smaller space within the room, the continuous talk generated aerosols are distributed throughout the room. Conclusion Within an indoor environment, 2m distancing will not be enough to protect healthy people from aerosols coming from an infected person due to continuous talking with prolonged exposure.

The purpose of the study is to investigate the dispersion of droplet nuclei/aerosol which are produced during coughing and continuous talking to quantify the risk of infection due to airborne disease transmission. A three-dimensional modelling of aerosol transport due to human respiratory activities such as coughing and talking within a room environment has been simulated using CFD technique. An inert scalar transport equation was used to represent aerosol cloud, while turbulence was modelled with the $$k-\epsilon $$ k - ϵ turbulence model. A modified Wells–Riley equation was used to calculate the risk of infection based on quanta emission concept. The spatial and temporal distribution of aerosol cloud within the room is initially driven by the upward flowing thermal plume surrounding the human, but later driven by the flow field constrained by the walls and cooler air movement. While the cough generated aerosols are concentrated in a smaller space within the room, the continuous talk generated aerosols are distributed throughout the room. Within an indoor environment, 2 m distancing will not be enough to protect healthy people from aerosols coming from an infected person due to continuous talking with prolonged exposure.

Numerical investigation of two-phase flow induced local fluctuations and interactions of flow properties through elbow. 2018 CHINENYE-KANU, N.M., HOSSAIN, M., DROUBI, M.G. and ISLAM, S.Z. 2018. Numerical investigation of two-phase flow induced local fluctuations and interactions of flow properties through elbow. In Wahab, M.A. (ed.