Three-dimensional numerical study of flow and species transport in an elevated jet in crossflow

摘要

The jet fluid coming out of the elevated source behaves as the efflux of exhaust gases from a stack and the crossflow stream representing the natural wind flow. Direct numerical simulations (DNS) in an elevated jet in crossflow have been performed at a Reynolds number of 250 and a Schmidt number of 7.25. The flow field and concentration distribution of pollutants have been explored by solving three-dimensional unsteady Navier-Stokes and species transport equations using second order spatial and temporal discretization. Three different blowing ratios (0.5,1.0 and 1.5) have been used to quantify the effect of blowing ratio on the flow field and pollutant dispersion. The blowing ratio is found have significant effect on both the flow and dispersion of pollutant. The evolution of various flow structures associated with the elevated jet in crossflow such as wakes, loop vortices is discussed. The instantaneous behavior of jet has been observed to be dependent on the unsteadiness of flow structures that varies with the blowing ratio. The downwash of jet has been observed at the lowest blowing ratio.