Direct Numerical Simulation and PIV Measurement of Turbulent Boundary Layer over a Rod-Roughened Wall
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- Lee SH., Lee J.H., Sung H.J. (2010) Direct Numerical Simulation and PIV Measurement of Turbulent Boundary Layer over a Rod-Roughened Wall. In: Nickels T. (eds) IUTAM Symposium on The Physics of Wall-Bounded Turbulent Flows on Rough Walls. IUTAM Bookseries, vol 22. Springer, Dordrecht
The effects of surface roughness on a spatially-developing turbulent boundary layer were investigated by performing direct numerical simulation and particle image velocimetry measurements of TBLs over rough and smooth walls. Introduction of the roughness elements augmented turbulent stresses in the region of y< 4 ∼ 5ks, where ks is an effective sand roughness height. However, the roughness has little effect on the vorticity fluctuations, turbulent kinetic energy budget and quadratic components of Reynolds shear stress in the outer layer. We also demonstrate the modification of coherent vortical structures over the rod-roughened wall by using linear stochastic estimation.