Local convective heat flux $\mathbf{J}(\mathbf{r})$ in turbulent thermal convection is obtained from simultaneous velocity and temperature measurements in a cylindrical cell filled with water. The measured $\mathbf{J}(\mathbf{r})$ in the bulk region shows a different scaling behavior with varying Rayleigh numbers compared with that measured in the plume-dominated regions near the sidewall and near the lower conducting plate. The local transport measurements thus allow us to disentangle boundary and bulk contributions to the total heat flux and directly check their respective scaling behavior against the theoretical predictions.

• Received 11 June 2007

DOI:https://doi.org/10.1103/PhysRevLett.100.244503