Convective transport of heat leads to many interesting natural phenomena and to important technical applications. Theoretically, the subject is very demanding. For this reason we have so far dealt with convection only briefly. In Chapter 7, we used a simple expression to calculate heat transfer at a solid-fluid interface. Knowing the heat transfer coefficient, we can establish a relation which serves as a boundary condition for processes inside a particular body. Uniform flow systems were discussed in Chapter 8, which led to expressions for entropy and energy transported by a fluid.