Date of Award

5-28-2024

Publication Type

Thesis

Degree Name

M.A.Sc.

Department

Mechanical, Automotive, and Materials Engineering

Keywords

Impinging jet;Submerged;Turbulent

Supervisor

Ram Balachandar

Supervisor

Majed Etemadi

Abstract

Impinging jets have become popular due to their versatility and adaptability in various applications, however very few studies have been conducted with a stand-off distance greater than eight diameters even with the wide array of fields where this application is utilized. This thesis examines a fully submerged impinging jet operating at a stand-off distance of 10 jet diameters and a Reynolds number of 38 500. The main findings are reported based on the computational results; however, an experimental study was done in parallel with identical operating conditions for validation purposes. The experimental portion was conducted using three-dimensional particle tracking velocimetry (3D-PTV). A Large-Eddy Simulation (LES) turbulence model combined with the WALE subgrid-scale model was used for the numerical analysis. It was discovered that the duration of coherence of the vortex street present just after the nozzle exit was lower than that of other cases with higher stand-off distances. Eventually these vortices merged to form large-scale structures which upon impinging on the plate, lead to the formation of secondary structures in the wall-jet region. Proper Orthogonal Decomposition was used to provide a better understanding of the higher energy containing structures in the domain. The highest energy structures were observed along the plate due to the turbulence generated from the jet striking the plate. The secondary structures found along the impingement surface on either side of the jet axis displayed both directions of rotation, along with varying energy levels. The breakdown of these secondary structures contributed to lower magnitude peaks in the wall shear stress distribution as the radial distance increased. Finally, a flapping mode was observed on the plate due to the asymmetric impingement of the large-scale structures. It was concluded that this mode correlates to the movement of the stagnation point on the impingement surface.

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