Effects of Time-Integration Method in a Large-Eddy Simulation Using PISO Algorithm: Part II - Thermal Field

In order to explore the effects of the time-integration method on the PISO (Pressure Implicit with Splitting of Operator) algorithm, large eddy simulation (LES) has been applied to turbulent thermal fields. To analyze the heat transfer, two conditions are adopted for a turbulent channel flow. Four variants are employed in the predictor step of the PISO algorithm. For the passive scalar field, the AB-CN and RK-CN schemes show good performance. However, some discrepancy appears in the cases of EULER and CN. Several simulations are performed for variable-density flows between two isothermal walls (T H /T C = 1.1, 2.0). The structure of the near-wall turbulence is changed by the temperature dependence of the fluid properties. However, the scaled velocity is collapsed into the law of the wall. For the selected cases, the dimensionless temperature on the cold side is high compared with that on the hot side. However, the temperature fluctuations exhibit larger values near the hot wall. This is closely linked to the variation of the fluid properties.