Investigation of cold-wire spatial and temporal resolution issues in thermal turbulent boundary layers

Abstract

In this study, we use simulations and experiments to investigate spatial and temporal attenuation of cold-wire sensors. A direct numerical simulation (DNS) of a heated smooth-wall turbulent channel flow is used to simulate the sensor spatial filtering effect in the spanwise direction, with results confirming that the increasing wire length does not affect the mean temperature, but significantly attenuates the variance of temperature fluctuations, especially in the vicinity of the wall. With increasing viscous-scaled wire length, the peaks of the one- and two-dimensional energy spectrograms of temperature fluctuations are increasingly attenuated, but in a manner that is approximately predicta..