Axis switching of pulsating jet issued from rectangular nozzle at low Reynolds number

What is it about?

Mixing and diffusion by jets ejected from nozzles are widely used in various engineering devices such as combustors and chemical reactors. In recent years, it has been necessary to develop efficient mixing enhancement techniques in low Reynolds number flow fields for the miniaturization of the device. One of the mixing promotion techniques is to use a non-circular nozzle. In this study, we perform a numerical analysis of a pulsating jet ejected from a rectangular nozzle at a low Reynolds number. To elucidate the relationship between vortex structures and axis switching, we investigate the formation of a vortex structure in the jet, the deformation process, the interaction between vortices, and the generated local turbulence.

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Photo by engin akyurt on Unsplash

Photo by engin akyurt on Unsplash

Why is it important?

In jets ejected from nozzles, a phenomenon occurs in which the major and minor axes of the cross-section of the jet are interchanged downstream. In this study, we investigated the occurrence mechanism of this axis switching in a pulsating jet at a low Reynolds number to clarify the influence of the nozzle aspect ratio on axis switching, deformation of vortex structures, and turbulence characteristics. As a result, it was found that axis switching can enhance the mixing effect at a low Reynolds number.

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