Numerical investigation into the blending characteristics of opposed wall jets in a finite field with different stagger distances

Abstract

Strong turbulence is generated by the blending of opposed staggered jets (OSJs). This turbulence results in fluid mixing and energy dissipation, which are crucial for pollutant dilution and the filling of navigation lock chambers. A renormalization group k-ε turbulence model is adopted to conduct three-dimensional simulations of OSJs at various stagger distances. The blending characteristics of two square water jets at eight stagger distances L* within a finite field are examined; here, L* is defined as the distance between the center lines of the staggered jets divided by the jet diameter. The initial Reynolds number and inlet diameter of the jets for the numerical simulations are set to 2.99 × 106 and 0.6 m, respectively. The numerical results show that there is a linear correlation between the decay exponent and the jet half-width, both of which increase and then gradually stabilize with increasing L*. Intriguingly, the vortex strength and blending length both increase at first before decreasing as L* increases, and the blending effectiveness distribution mirrors these fluctuations. Moreover, a decay model for the axial velocity is formulated in terms of the decay exponent and L*. These investigations yield substantial theoretical results underpinning fluid mixing and orifice arrangement in navigation lock chambers.