Horizontal pipe, mixed convection

Secondary flow in mixed convection in a horizontal pipe. 

There have bee.i many studies of internal mixed convection, particularly in circular pipes. The conditions under which flow in a circular pipe can be assumed to be purely forced convective, purely free, and mixed convective have been presented in graphical form by Metais and Eckert [62], the form of these graphs being given in Figs. 9.26 and 9.27. Figure 9.26 applies to flow in a vertical pipe while Fig. 9.27 is for flow in a horizontal pipe. j... 

Regimes for purely forced, purely free, and mixed convection for flow through horizontal pipes [62],... 

With mixed convective flow in a horizontal pipe the buoyancy forces act at right angles to the direction of forced flow leading to the generation of a secondary motion as discussed earlier. The equations governing this type of flow will be briefly discussed in this section. 

Wang, M., Tsuji, T., and Nagano, Y., Mixed Convection with Row Reversal in the Thermal Entrance Region of Horizontal and Vertical Pipes , Int. J. Heat Mass Transfer, Vol. 37, pp. 2305-2319,1994. 

---