Fluctuating pressure measurements in a turbulent separation bubble

Bubble breakup in a turbulent shear layer

The breakup of a millimetre size buoyantly rising bubble encountering a horizontal plane turbulent jet is experimentally investigated using high-speed shadowgraphy and acoustic techniques. The bubble diameter to jet height ratio is 0.75 and the jet height based Reynolds number is 4000. The high-speed imaging was recorded at 7 kHz simultaneous with hydrophone output at 100 kHz. Bubble breakup ev...

Numerical Simulation of Scaling Effect on Bubble Dynamics in a Turbulent Flow around a Hydrofoil

A Lagrangian-Eulerian numerical scheme for the investigation of bubble motion in turbulent flow is developed. The flow is analyzed in the Eulerian reference frame while the bubble motion is simulated in the Lagrangian one. Finite volume scheme is used, and SIMPLEC algorithm is utilized for the pressure and velocity linkage. The Reynolds stresses are modeled by the RSTM model of Launder. Upwind ...

Turbulent Spot/Separation Bubble Interactions in a Spatially Evolving Supersonic Boundary-Layer Flow

The growth and breakdown of localised disturbances into a turbulent spot in a Mach 2 boundary-layer flow have been investigated by direct numerical simulation. In particular, the interaction of a turbulent spot with a shock-induced separation bubble is studied. The primary vortex structures triggered by the injected low momentum fluid and the metamorphosis of the hairpin structures into a turbu...

Measurements of streamwise and spanwise fluctuating velocity components in a high Reynolds number turbulent boundary layer

Measurements of the streamwise and spanwise fluctuating velocity components are obtained in a high Reynolds number turbulent boundary layer using custom made sub-miniature hot wires. These measurements are made over a range of Reynolds numbers from Reτ ≈ 3,000 to Reτ ≈ 10,500, but at fixed unit Reynolds number U∞/ν (Reτ = δUτ/ν; where ν is the kinematic viscosity, Uτ is the friction velocity an...

Properties of the Fluctuating Wall-pressure Field of a Turbulent Boundary Layer