The present study examines the configuration of an offset jet issuing into either a quiescent medium or a moving stream (co-flowing). The mean velocity and turbulence characteristics of the turbulent offset jet have been investigated using a particle image velocimetry technique at three velocity ratios and for two offset ratios. A numerical simulation of a threedimensional offset jet has also been carried out by comparing the corresponding results with previous experimental data and our measurements. The numerical investigation was performed by means of the finite volume method together with a second-order turbulent closure model -the Reynolds stress model (RSM) -to examine the behavior of the flow for different velocity ratio and offset ratios. Results give a satisfactory agreement between the experimental data and the calculations. Data from the early flow region clearly show a significant influence of the velocity ratio and the offset ratio on the mean flow and turbulence characteristics.

International audienceAn experimental and numerical investigation of the flow field of variable density turbulent offset jet is presented. The velocity measurements are performed using a Velocimetry Laser Doppler technique for an offset height h. Three cases of variable-density turbulent plane jets discharging from a rectangular nozzle into a quiescent medium are studied. The variation density jets considered were revealed at different Reynolds numbers. In the second step of this work, a numerical three-dimensional model of the problem is simulated through the resolution of the Navier-Stokes equations by means of the finite volume method and the Reynolds stress model second-order turbulent closure model. A non-uniform mesh system tightened close to the emitting nozzle and both the vertical and horizontal walls is also adopted. A good level of agreement was achieved, between the experiments and the calculations. Once the model validated, our model allowed the evaluation of the influence of the variation density on the characterizing features of the resulting flow filed. It is found that the centerline velocity and concentration of the heavier jet decays much faster than in the two other jets, and a similar behavior for the vertical profiles in the three variable-density jets is well reproduced in the simulation

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Sixth Conference on Design and Modeling of Mechanical Systems (CMSM 2015), Hammamet, TUNISIA, MAR 23-25, 2015International audienceA dynamic study of the mean flow behavior of a three-dimensional turbulent offset jet issuing into a quiescent ambient is presented. The flow is characterized by a longitudinal variation of curvature, skewed impingement onto a flat surface, a recirculating region, and the development of a wall jet region. A numerical simulation is used, by means of the finite volume method with the second order turbulent closure model: the Reynolds stress Model (RSM), to investigate the influence of certain parameters such as jet discharge height and the geometric nozzle. Flow structure is described in the preimpingement, recirculation and impingement regions. Interdependence is shown among the offset height (h) and the geometric nozzle (plane jet and circular jet). The obtained results are presented in terms of the jet dimensionless velocity distribution, maximum velocity decay and vectors velocity of the flow. The jet decay is presented. The recirculation region is fed by a relatively strong backflow for the reported high offset height and it is shown that the reattachment point depends strongly with the jet form and the offset height