Abstract
This paper describes the result of the numerical analysis of the heat transportation in a double tube. It was found that a unique type of oscillatory flow was induced in the double tube when a simple sinusoidal reciprocating flow was imposed at one end of the tube. The unique oscillatory flow was a reciprocating flow superimposed with a steady circulation flow. The present double tube can transport heat with a high efficiency that is mainly attributed to the heat transportation by the steady circulation flow.
