Effect of corner angle on convection enhancement in wavy ducts with trapezoidal cross-sections

The effect of corner angle variations on pressure drop and heat transfer characteristics is investigated in the fully developed region of wavy ducts with trapezoidal cross-sections. The resulting enhancement of convection, with respect to corresponding straight ducts, can be attributed to the formation of longitudinal vortices close to the two parallel surfaces. Numerical simulations show that Nusselt numbers and friction factors increase with the decrease of corner angle from 90 to 60degrees, before levelling out around 60degrees. Nusselt numbers and friction factors also increase with the Reynolds number, and the slopes of their representative curves increase above a critical value of the Reynolds number because of the onset of time-periodic flow oscillations. Copyright (C) 2004 John Wiley Sons, Ltd.