Abstract: A numerical investigation of a2-D flow passage with two rib heights is presented in this study．The calculated results indicate that the angles between temperature gradient and velocity in the heat transfer sub-layer influence heat transfer of the whole turbulent region．The mechanism of heat transfer augmentation on the passage is analyzed‚and a new way to vary the layer is presented to control two fields synergy．Thus the Field-Synergy Theory is extended within the fully-developed turbulent flowing field．

Key words: rib, turbulent flow, numerical inve stigation, the Field-Synergy Theory