ME5E04: A dual jet is formed through the combination of a wall jet and an offset jet, where the initial direction of the fluid at the nozzle: Computational Fluid Dynamics Assignment, TCD, Ireland

A dual jet is formed through the combination of a wall jet and an offset jet, where the initial direction of the fluid at the nozzle exit is parallel for both jets. The term ‘wall jet’ is given to a stream of fluid discharged tangentially to a solid wall, whereas an offset jet flows parallel to a wall boundary but offset by some distance.

The resulting flow behavior through the amalgamation of these two jet types is highly complex and distinctly different from that of a wall jet or offset jet individually. As the jets are issued simultaneously from the nozzle exit, a low-pressure region or recirculation zone is created between the wall jet and the offset jet, which causes the offset jet to deflect towards the wall and
merge with the wall jet at some downstream distance, i.e., the merge point.

Following this, the two jets continue to interact before becoming fully combined, at the combined point, beyond which the dual jet will behave in a similar manner to an equivalent single wall jet. While both wall jets and offset
jets have each been studied extensively, the combination of such is severely underrepresented in the literature.

Of those studies which have been dedicated to dual jet flow, the majority have been entirely numerical in nature and, to our knowledge, only a single experimental investigation regarding dual jets has been published to date. However, this study only considered the fluid flow behavior, meaning the heat transfer characteristics associated with dual jet flows are yet to be explored through experimentation.

The general flow structure associated with a dual jet can be seen in Figure 1. The schematic shows two rectangular slot jets, a wall jet, and an offset jet, emerging into the quiescent ambient from the same vertical plane, with initial parallel streamwise mean velocities of 𝑈𝑤 and 𝑈𝑜 respectively at the nozzle
exit.

Both jets are issued in the positive 𝑥-direction, where the origin of the coordinate system is located at the intersection between the jet exit plane and the bottom wall. In the figure, the characteristic jet width, denoted by 𝑤, refers to the jet dimension in the 𝑦-direction, and is identical for both jets in this figure, though in your study you may wish to vary this parameter. Keep in mind
that if you do vary the jet width, the appropriate definition of the Reynolds number may change.