Consider the fow of a fluid through a long circular tube. a) In the case of spatially-uniform and constant heat fux from the tube wall to the fluid, on the

same graph sketch the evolution of the inner-surface temperature of the tube and of the mean temperature of the fluid as functions of the stream wise coordinate in fully developed conditions.Explain how the slopes of the two temperature curves are related to the wall heat flux per unit area.[3 marks) b) In the case of spatially-uniform and constant inner-surface temperature of the tube, on the same graph sketch the evolution of the inner-surface temperature of the tube and of the mean temperature of the fluid as functions of the stream wise coordinate. Explain the concept of log-mean temperature difference and how this difference is related to the heat transfer cate from the inner surface to the fluid. c) In the case of constant surface temperature, what is the mean temperature of the fluid at a very large downstream distance? Explain Your answer.12 marks)