This paper investigates the influence of a weak-jet on the development of a turbulent axisymmetric strong jet. A parametric study is carried out to evaluate simultaneously the effect to the Jets-spacing (S/D=3 and S/D=7. 5) and their velocity ratios in range 0≤ λ ≤ 1. The mixing phenomenon is studied numerically by the finite volume method using the 3D-RANS second-order model, which gives a good agreement with the available data. Three distinct regions of this type of Jets interaction are evidenced. This study confirms that the Jets spacing affects strongly the converging region and has a minor effect on the combining region. It is found that the weak jet attracts the strong jet and the combining region extends from 30D to 40D where the self-similarity of a single jet is obtained. The jet width decreases when velocity ratio and Jets spacing augment. In the combining region, in comparison with the free jet, it is found that the addition of a weak-jet increases the decay rate of the centerline velocity.

In the present investigation, we propose a numerical simulation of Two plane parallel turbulent Jets. Several turbulence models were tested in the present work: the standard k   , the standard k   and the RSM models. A parametric study was also presented to pick up the nozzle spacing and the velocity ratio effect on the merge and combined point’ s axial and transverse positions. An investigation on the velocity ratio effect on the strong and weak jet spreading was also performed. It has been shown through the present investigation that the velocity ratio significantly affects the position of merge and combined points. Correlations between the merge and combined points position with respect to the nozzle spacing and the velocity ratio are also provided. Results show that the increase in the velocity ratio moves the merge and combined points further upstream in the longitudinal direction while deflecting toward the strong jet in the transverse direction. The present numerical investigation allows us to conclude that when increasing the velocity ratio, the weak jet exercises some braking on the strong jet which decelerates its spread. On the other hand, the strong jet produces some acceleration on the weak jet, which enhances its spread.

Throughout history, human societies have been affected by various epidemic and pandemic infectious diseases. Careful archaeological and historical work has revealed that intersecting social and economic inequalities shaped the course of epidemics. Bioarchaeology and other social sciences have repeatedly demonstrated that these kinds of crises play out along the preexisting fault lines of each society. The people at greatest risk were often those already marginalized—, the poor and minorities who faced discrimination in ways that damaged their health or limited their access to medical care even in prepandemic times. In turn, the pandemics themselves affected societal inequality, by either undermining or reinforcing existing power structures. That reality is on stark display during the COVID-19 pandemic. Although the disease has memorably struck some of the world’, s rich and powerful, it is not an equal-opportunity killer. The death toll is higher in poorer and denser areas because they have already suffered from poor health, poverty, and malnutrition.

This paper discusses the hot subsonic and near-sonic axisymmetric submerged stationary Jets flowing from a nozzle with a radius of 25. 4 mm. The Mach number at the nozzle exit is 0. 376 for a subsonic jet, and for a near-sonic jet, it is 0. 985. The Reynolds number for both problems was equal to 5600. A Two-fluid turbulence model was used to study these problems. The numerical results of this model were obtained for both the full elliptic and simplified parabolic systems of equations. The SIMPLE procedure was applied to the numerical implementation of the complete elliptic system of equations. In the parabolic system of equations, the marching method of integrating equations in the longitudinal direction is used. The results of the Two-fluid model are compared with the results of other known RANS turbulence models, which were obtained using the COMSOL Multiphysics® package, as well as with the experimental data from the NASA database.