ABSTRACT
This chapter concludes the book by examining entropy and the Second Law for turbulent flows. It presents an overview of modeling and experimental methods for determining entropy production in turbulent flows. The turbulent entropy equation will be derived from the Reynolds averaged Clausius-Duhem equality (Hauke, 1995), which expresses entropy in terms of mean and fluctuating components in the Reynods averaging. A small thermal turbulence assumption (STTAss) will be used in the turbulence analysis (Kramer-Bevan, 1992). Under the STTAss, the fluctuating component of temperature is assumed small compared with the mean temperature, which allows the mean turbulent entropy production to be expressed in terms of viscous mean and turbulent fluctuating parts.
