Motion of sphere in a stratified fluid

The unsteady motion of a sphere in a viscoelastic fluid

The structure of the near wake of a sphere moving horizontally in a stratified fluid

We present experimental results for the wake structure of spheres moving in homogeneous and stratified fluid. In homogeneous fluid, the results of Kim & Durbin (1988) are confirmed and it is shown that the two characteristic frequencies of the wake correspond to two instability modes, the Kelvin-Helmholtz instability and a spiral instability. For the stratified wake four general regimes have be...

Numerical Study of a Descending Sphere in a Low Reynolds Number Strongly Stratified Fluid

The flow generated by a sphere descending uniformly in a linearly stratified diffusive fluid is investigated numerically for different Reynolds (Re) and Froude (F ) numbers. The parameters used for the simulations were 10 ≤ Re ≤ 10 and 10 ≤ F ≤ 10, keeping the Schmidt number, Sc (= 700, typical of sea water) fixed. The results demonstrate drag dependence on viscosity and stratification, suggest...

Rising motion of a swarm of drops in a linearly stratified fluid

Direct numerical simulations of a swarm of deformable drops rising in density stratified fluids are presented at intermediate Reynolds numbers. All flow scales are fully resolved using front-tracking/ finite-volume method. The average rise velocity and velocity fluctuations of the swarm are reduced in the presence of density stratification. The isotropy in velocity fluctuations is enhanced as t...

Motion of a sphere normal to a wall in a second-order fluid

The motion of a sphere normal to a wall is investigated. The normal stress at the surface of the sphere is calculated and the viscoelastic effects on the normal stress for different separation distances are analysed. For small separation distances, when the particle is moving away from the wall, a tensile normal stress exists at the trailing edge if the fluid is Newtonian, while for a second-or...