DNS of starting turbulent jets with variable density

Abstract

Abstract We study starting turbulent round jets with variable density using Direct numerical simulations (DNS). A fully developed turbulent air flow at constant Reynolds number Re = 5300 is injected to space, filled with air, carbon dioxide or helium with a small co-flow, with variable density being due to the mixing of different gases. We compare the celerity factor, centreline velocity and dynamics of the vortex dipole in front of the jet between all the considered cases.