Finite-Element Analysis of Convection Problems in Spatially Periodic Domains

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

“…The reliability of the calculation procedure described in previous sections had already been demonstrated [11][12][13]. However, the accuracy has been assessed once again here by imposing periodicity conditions on small portions of straight trapezoidal channels characterized by di erent corner angles.…”

“…In periodic fully developed ows, the pressure p can be expressed by the sum of a linear term, accounting for the mean pressure gradient, and a residual term that behaves in a periodic manner (see, for example, References [11,18]). Thus, for the situation illustrated in Figure 1, the pressure can be estimated as…”

“…is obtained [11]. In Equation (8) S is the area of a surface parallel to the in ow/out ow boundaries and n is the unit vector normal to the surface.…”

“…The anti-periodic boundary conditions are introduced as illustrated in detail in References [11][12][13]. The momentum and energy equations are discretized with respect to time, in a form that allows the selection of di erent time-integration schemes.…”

“…We will consider fully developed convection of air (Pr = 0:72) with ows in the laminar regime, both below and above the critical value of the Reynolds number. The approach adopted here has been originally proposed in Reference [11] and has been recently used to investigate pressure drop and heat transfer characteristics in fully developed regions of wavy ducts [12,13]. In Reference [12] the in uence of space ratio H=L and corrugation angle ÿ has been investigated in two-dimensional wavy channels.…”