Sixth International Symposium on Turbulence and Shear Flow Phenomena
DOI: 10.1615/TSFP6
Turbulent Schmidt Number Measurements in a Polymer Drag-Reduced Turbulent Boundary Layer
pages 73-78
DOI: 10.1615/TSFP6.110
ABSTRACT
In this work we investigate zero pressure gradient turbulent boundary layer (TBL) drag reduction (DR) by polymer injected from a single upstream slot using simultaneous Particle Image Velocimetry (PIV) and Planar Laser Induced Fluorescence (PLIF). The data allow the computation of the turbulent fluxes in the streamwise and wall-normal directions. The results show a suppression of fluxes at positions closer to the injection slot where the drag reduction is highest, with a recovery towards an undisturbed boundary layer with downstream distance. The turbulent Schmidt number is computed and shown to be as high as 5 at high drag reduction and reducing towards unity as drag reduction decreases.