The calibration data of two cone-shaped platinum thin film turbulence probes used for oceanic measurements show that the rate of heat transfer from the film to the fluid is not proportional to U01/2 as expected for a constant temperature conical surface. A thermal model of the probes that agrees favorably with the calibration data indicates that this nonproportionality is due to the thermal effect of the glass coating over the film and glass substrate below it. The unsteady heat flux from the film in response to variations in the ambient fluid's speed increases with increasing frequency above 100 Hz. It is shown that the unsteady heat flux is proportional to the unsteady viscous surface stress over the film, which increases in magnitude with increasing value of the frequency parameter ωL/3U0. The ratio of the temperature-to-velocity sensitivity is highest at zero frequency. |