R. Kaiser, S. Moller, R. du Puits

"Tomographic PIV at the Barrel of Ilmenau: length scale analysis of the viscous boundary layer"

At the Barrel of Ilmenau, we performed measurements of all velocity components in a small volume below the central region of the cooling plate using tomographic PIV. The measurements were conducted in a Rayleigh number range 10^8 < Ra < 10^12 to verify and to characterize the transitional behaviour of the near wall flow. Based on this velocity data set, the inner and the outer length scales of the boundary layer introduced by Scheel and Schumacher 2014 are investigated. The conducted measurements confirm the scaling behaviour of these length scales found by the DNS and extend its validity up to Ra=10^12.