Low-frequency pressure fluctuations in axisymmetric turbulent boundary layers

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...

Coherent structures in turbulent boundary layers with adverse pressure gradients

The coherent structures in turbulent boundary layers (TBLs) subjected to adverse pressure gradients (APGs) were investigated by analyzing a database of direct numerical simulations. The equilibrium adverse pressure gradient flows were established by using a power law free-stream distribution. The population trends of the spanwise vortices show that the outer regions of the APG TBLs are densely ...

Instabilities in turbulent boundary layers

An investigation of a model of turbulence generation in the wall region of a turbulent boundary layer is made through direct numerical simulations. The model is based on the instability of a streak. First, a laminar boundary layer disturbed by a continuous blowing through a slot is simulated in order to reproduce and further investigate the results reported from the experiments of Acarlar & Smi...