Experimental setup

We have carried out PIV measurements near roughness in turbulent thermal convection inside the Barrel of Ilmenau. The cell height is 2.5 m, 10 times larger than our water cell in Lyon, at nearly the same Rayleigh numbers. The combined experiments (Ilmenau and Lyon) will allow us to extent our recent results on the boundary layer structure near roughness.

Figure 1: Picture of the experimental setup inside the Barrel.

Preliminary results

The measurements indicate a change of boundary layer properties at low and high Rayleigh numbers.

Figure 2: Streamplots inside a notch at low Ra (top) and at high Ra (bottom).

Movies

• Movie inside the notch (low Ra)
• Movie on the top of the obstacles (low Ra)
• Movie in the groove (low Ra)
• Movie inside the notch (high Ra)
• Movie on the top of the obstacles (high Ra)
• Movie in the groove (high Ra)