Application of Structure Functions for the Investigation of Forced Air   Cooling
  This paper presents thermal analyses of a power amplifier placed in a wind tunnel. All the investigations are based on the transient temperature measurements performed during the circuit cooling process. The measured cooling curves were used to compute the cumulative and differential structure functions for the circuit with a heat sink. These functions helped to determine the optimal values of circuit model parameters necessary for numerical thermal simulations. The experiments demonstrated the influence of the wind speed on the value of the heat transfer coefficient and consequently on the temperature of the entire structure. 
M. Janicki, Jedrzej Banaszczyk, G. De Mey, M. Kaminski, B. Vermeersch,   A. Napieralski