Experimental study of the stratified wake of a sphere: Internal Waves

Wakes in density-stratified fluids radiate internal waves due to the random turbulent motions in the core of the wake (Meunier et al. JFM 2018; Rowe, Diamessis, and Zhou JFM 2020). To investigate the relationship between the core turbulent wake and the resulting internal waves, experiments with a dimpled sphere at Reynolds number of ~100,000 and Froude number of ~64 were conducted using. The experiments extend prior unstratified wake results of Saunders et al. (PRF 2020; Exp. Fluids 2022) to the stratified regime. This presentation will focus on the radiated internal waves extending to a dimensionless time of Nt ~ 50, where N is the buoyancy frequency.