The response of a turbulent boundary layer to a double step-change in a wall heat flux

Extensive measurements were made of the response of a turbulent boundary layer to a double step change of wall heat flux. The measurements include mean temperature and velocity as well as temperature-velocity correlations up to third order occuring in the transport equations together with the skewness and flatness of temperature fluctuations. Two thermal layers start to develop within the primary boundary layer due to the change in heat flux at the boundary. These layers are characterized by different growth rates which depend on the wall heat flux. Most of the changes in the downstream stations take place inside the second thermal layer.