Large-Eddy Simulation of a Turbulent Boundary Layer With Blowing

The modifications of a turbulent boundary layer induced by blowing through a porous plate are investigated using large-eddy simulation. The Reynolds number (based on the length of the plate) of the boundary layer is about 850,000. In order to simulate the fully developed turbulent boundary layer, an instationnary inflow condition is used. Influences of the fluid injection rate upon the three components of the velocity are characterized and a good agreement is obtained when comparing with previous experimental measures. Evolution of the mean and root-mean square parts of the velocity with injection rate is studied. It is observed that the maximum of the fluctuations of the longitudinal velocity slowly increases with blowing but the size of the domain where the fluctuation level is high, rapidly grows. For the vertical and transverse components, the fluctuating profiles are almost multiplied by two. Finally, blowing is shown to increase the level of the near-wall structures as well as the physical space where they develop.