APPLICATION OF A REFLECTION-FREE DSM TO TURBULENT-FLOW AND HEAT-TRANSFER IN A SQUARE-SECTIONED U-BEND

The paper reports the outcome of applying two differential second-mome nt (DSM) closures to resolve the complex three-dimensional motion that arises in turbulent flow in a square-sectioned duct passing around a 180 degrees C bend. The initial results showed (in accord with a numbe r of recent studies) that, with the same underlying closure hypotheses , a DSM scheme produces better agreement with experiment than does the corresponding algebraic second-moment (ASM) treatment, although the d ifferences were acceptably small. Thereafter, applications are reporte d for a new type of DSM that employs no wall-reflection terms. This le ads to markedly better predictions of the turbulence field and thus of the wall heat transfer than the conventionally adopted version. (C) E lsevier Science Inc, 1996