FLUENT provides the ability to calculate streamwise-periodic--or "fully-developed''--fluid flow. These flows are encountered in a variety of applications, including flows in compact heat exchanger channels and flows across tube banks. In such flow configurations, the geometry varies in a repeating manner along the direction of the flow, leading to a periodic fully-developed flow regime in which the flow pattern repeats in successive cycles. Other examples of streamwise-periodic flows include fully-developed flow in pipes and ducts. These periodic conditions are achieved after a sufficient entrance length, which depends on the flow Reynolds number and geometric configuration.
Streamwise-periodic flow conditions exist when the flow pattern repeats over some length , with a constant pressure drop across each repeating module along the streamwise direction. Figure 9.4.1 depicts one example of a periodically repeating flow of this type which has been modeled by including a single representative module.
Limitations for Modeling Streamwise-Periodic Flow
The following limitations apply to modeling streamwise-periodic flow: