Dependence of wall jet phenomenology on inlet conditions and near-field flow development

Abstract

In this paper, the three-dimensional turbulent wall jet flow is investigated for three different developing initial velocity profiles. $k-$ The developing initial velocity profiles at the nozzle exit are generated by three different lengths ($l/h=10$, 50 and 90) of the square nozzle $(20\pm 0.5\mathrm{mm}\times 20\pm 0.5\mathrm{mm})$. The velocity profiles at the nozzle exit are measured with the single probe hot-wire anemometer. The Reynolds number based on the bulk mean velocity and nozzle height is 25,000 for all the cases. The measured velocity profiles at the nozzle exit are used as the inlet conditions for the numerical simulations. The results show that the initial velocity profile affects the flow field of the wall jet in near and far-field regions. It is found that the contours of streamwise velocity and turbulent kinetic energy exhibit the effect of initial conditions in the near field. $l/h=50$ $l/h=90$ The Reynolds shear stress component $⟨u^{\prime }{v}^{\prime }⟩$ dominates in the vertical jet centreline plane, and it increases with a decrease in the nozzle length. The Reynolds shear stress component $⟨u^{\prime }{w}^{\prime }⟩$ dominates in the lateral plane, and also exhibit the dependency on initial conditions.

Keywords:

• three-dimensional wall jet
• numerical result
• low Reynolds number model
• experimental result
• jet inlet velocity profile

Disclosure statement

No potential conflict of interest was reported by the authors.