On hairpin vortices in a transitional boundary layer

Dns of the Generation of Secondary -vortices in a Transitional Boundary Layer

Especially for large amplitude initial disturbances so called vortices de velop during the non linear late stages of laminar turbulent transition Once formed they may persist as so called hairpin vortices well into the ensuing turbulent boundary layer This makes their study important for under standing transition and turbulence in wall bounded shear ows In Direct Numerical Simulations DNS as we...

Direct measurement of hairpin-like vortices in the bottom boundary layer of the coastal ocean

Electromagnetic Control of a Transitional Boundary Layer

We investigate numerically the transition to turbulence in a flat-plate boundary layer controlled by electromagnetic forces. The fluid considered is incompressible, Newtonian and low electrically conductive. Similar to boundary layer suction, when applying a steady, wall-parallel, and streamwise oriented Lorentz force, the Blasius velocity profile is transformed to an exponential one. Since the...

Surface Friction and Boundary Layer Thickening in Transitional Flow

Boundary layer turbulence in transitional and developed states

Using the recent DNS by Wu and Moin (2010) of a flat-plate boundary layer with a passively heated wall, statistics of the turbulence in transition at Reθ = 500 where spots merge (distributions of the mean velocity, rms velocity and vorticity component fluctuations, kinetic energy production and dissipation rates and enstrophy) have been compared to these statistics for the developed boundary la...