| A computer program has been developed which simulates internal flows with recirculating zones in planar and axisymmetric geometries. The boundary layer equations are initially solved to identify the regions of separation, and then the incompressible Navier-Stokes equations, in a stream function-vorticity formulation, are solved for regions of the flow where the boundary layer approximations do not apply. Turbulence closure is via a low-Reynolds number two-equation model of turbulence. The program is verified by calculation of flows for which exact analytic solutions or experimental results are available.;The boundary layer equations are shown to yield satisfactory predictions of heat transfer, even in cases involving significant recirculating zones. The numerical technique developed has shown that simulation of complex turbulent flows on mid-size computers is feasible.;Laminar and turbulent attached flow cases considered in the study are fully-developed and developing flows in pipes and channels, with and without heat transfer. Laminar separated flows cases that are studied include flow over symmetric and asymmetric channels with abrupt expansions, periodic converging-diverging pipes, and flow over rectangular roughness elements in a channel. A turbulent case for flow over an asymmetric back-facing step is examined, showing agreement with experimental results. Turbulent flow in a periodically converging-diverging pipe is simulated, with results showing that, for equivalent hydraulic diameter Reynolds numbers, heat transfer is enhanced over the constant cross section case, but at the cost of an increase in pressure drop. Turbulent flow over rectangular roughness elements is examined, with the results showing heat transfer is augmented, similar to that in a separate experimental study. |
