Weno-Hydro Buoyant Gallery
Lock Exchange problem.
The lock-exchange system consists of fluids of different densities separated by a sharp vertical interface. Small disturbances are amplified to form large scale vortical motions which break down into random turbulent motions accompanied by scalar mixing.
Figure 1. Density contours at different time instances in a lock exchange system. Time increases from top to bottom. Red denotes lighter and blue denotes denser fluid.
Denser fluid overlies lighter fluid, separated by a horizontal interface. This essentially unstable system forms finger-like structures as it undergoes overturning and mixing
Figure 2. Snapshots of density contours in a thermal instability system. Time increases from left to right. Red denotes lighter fluid while blue denotes denser fluid.
Steady buoyant jet
A lighter fluid jet is injected horizontally into surroundings of heavier density. The lighter jet rises vertically due to buoyancy as it moves across the length of the domain. The figure below shows a non-buoyant jet adjacent to a buoyant jet. The vertical displacement of the buoyant jet (right panel) is apparent.
Figure 3. Vorticity iso-surfaces with vorticity magnitude projected on the transverse plane for a non-buoyant jet (left) and buoyant jet (right).
Differentially heated cavity
A three-dimensional box containing fluid is heated on one side and cooled on the other side. Fluid near the heated wall becomes lighter and rises to the top, while fluid near the cooled wall becomes denser and sinks to the bottom setting up convection currents.
Figure 4. Temperature iso-surfaces (left) and vorticity iso-surfaces (right) in a differentially heated cavity.
Starting buoyant jet
Lighter fluid is injected for a short interval of time into an initially stationary surrounding. The fluid rolls up into a starting head vortex, followed by a trailing stem. The figure below shows snapshots at different instances of time as the lighter fluid penetrates into the stationary fluid. The turbulent structures are dissipated once injection into the domain ceases.
Figure 5. Vorticity iso-surfaces with transported scalar contours projected on the transverse plane for a starting buoyant jet. The four images represent snapshots at four different time instances with time increasing from left to right.