The temperature statistics of a surfactant-covered air/water interface during mixed convection heat transfer and evaporation

Surface temperature fields were measured of an air/water interface where heat was transferred from the water to the air under mixed convection conditions. The interfacial temperature field was measured using an infrared (IR) camera for mean wind speeds ranging from 0 to 4.0 m/s, in 1.0 m/s increments. Statistics of these surface temperature fields, specifically, the root mean square (rms) and the skewness were obtained. Plots of the rms versus the heat flux showed linear behavior for low wind speeds (U = 0–3 m/s), and the skewness was also found to increase with heat flux for U = 0–3 m/s, although these data exhibited significant scatter. The scaled root mean square temperature was revealed to be governed by the ratio Ra1/3/(Re∗4/5Pr1/3) where Ra is the Rayleigh number, Re∗ the Reynolds number based on water side friction velocity and Pr is the Prandtl number.