Scaling properties of the mean wall-normal velocity in zero-pressure-gradient boundary layers

Evolution of zero pressure gradient turbulent boundary layers

The streamwise evolution of a turbulent boundary layer (TBL) developing under constant pressure on a smooth wall is considered. The closure problem is described for the zero pressure gradient (ZPG) flow where the only assumptions made are the use of classical similarity laws, such as Prandtl’s law of the wall and Coles’[1, 2] law of the wake, together with the mean continuity and mean momentum ...

Scaling structure of the velocity statistics in atmospheric boundary layers

The statistical objects characterizing turbulence in real turbulent flows differ from those of the ideal homogeneous isotropic model. They contain contributions from various two- and three-dimensional aspects, and from the superposition of inhomogeneous and anisotropic contributions. We employ the recently introduced decomposition of statistical tensor objects into irreducible representations o...

Wall-pressure Fluctuations and Pressure-velocity Correlations in Turbulent Boundary Layers

Constant adverse pressure gradient turbulent boundary layers

Significant progress has been made towards understanding the large scale features of wall-bounded shear flow in zero pressure gradient (ZPG) turbulent boundary layers (TBL). Here we consider their effects in adverse pressure gradient (APG) flows where the pressure gradient parameter is held constant and Reynolds number is varied. This is done by documenting the changes in the mean velocity, str...

Zero crossings of velocity fluctuations in turbulent boundary layers

In this paper some results are presented on the statistical properties of zero crossings of turbulent velocity fluctuations in boundary layers over a wide range of Reynolds numbers. The earlier finding that the probability density function (pdf) of the intervals between successive zero crossings of the streamwise velocity fluctuation u can be approximated by two exponentials, ,* each with its o...