Response of a nonevaporating monodisperse spray in a uniform laminar gas flow to acoustic perturbations

Understanding the interaction between an acoustic field and a dispersed cloud of droplets in particle-laden flows is critical, particularly for thermoacoustic instabilities in spray flame combustors. This study develops analytical expressions for particle velocity and number density, leading to insights into the particle clustering mechanism. While individual droplets may remain largely unaffected by acoustic perturbations, the droplet population spatial distribution can still undergo significant disturbances. An evanescent convective wave in the particle velocity response is identified as the primary driver of clustering, which is predominantly a convective phenomenon at low Mach numbers.