A computational study of particle dynamics in synthetic jet flow field

Abstract

This computational study aims to investigate the transport and dispersion of solid particles in a synthetic jet flow field. Solid spherical particles were injected into the jet at a single point, and their behavior was observed until they left the domain. The interaction between the particles and the vortex rings in the jet was compared for synthetic jets, with different Strouhal numbers (0.05, 0.1, and 0.2). The Reynolds number (Re = 150), the mass of injected particles, particle diameter distribution, and particle Stokes number at injection were kept constant. The results showed that the jet's momentum mainly transported the particles, while the vorticity of the vortex rings caused them to spread. The particle Stokes number affected the distribution of particles within the jet, with a higher Stokes number particle concentrating at the jet's center and lower Stokes number particles being carried within the vortex ring. For the low Strouhal number jet, the combined effect of the fast decline in the particle Stokes number, low vorticity of vortex ring, significant distance between successive vortices, and high jet momentum resulted in a higher spread of particles and rapid transport across the domain. As the Strouhal number increased, the particle Stokes number decreased slowly downstream; moreover, the vorticity of the vortex ring increased, the distance between vortices decreased, and low momentum imparted by the jet led to less particle spread and slower transport. Overall, the spread and transport of particles were most effective in the synthetic jet, with the low Strouhal number.