Experiments and simulations of low Re sphere wakes with and without stratification

Near wakes behind a sphere in both homogeneous and linearly stratified background were studied numerically and experimentally at Reynolds number Re ≤ 1000, Froude number Fr ≥ 0.5. In a homogeneous fluid, the structural transitions with increasing Re are consistent with previous studies. The stratified results from simulations and experiments are in good agreement. Stratified wakes undergo similar transitions with decreasing Fr for Re in current range, except that similar transitions occur at larger Re as Fr decreases, thus making the wake structure at high Re, low Fr similar to that at low Re, high Fr.