Direct numerical simulation of thermal channel flow for medium–high Prandtl numbers up to Reτ=2000

• Published in: International journal of heat and mass transfer 2021-09, Vol.176, p.1, Article 121412
• Main Authors: Alcántara-Ávila, F., Hoyas, S.
• Format: Article
• Language: English
• Subjects: Boundary conditions; Channel flow; Computational fluid dynamics; Direct numerical simulation; DNS; Fluid flow; Heat transfer; Prandtl number; Reynolds number; Thermal energy; Thermal simulation; Turbulent budgets; Websites
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2021.121412

•New set of DNS for a new combination of friction Reynolds and Prandtl numbers, up to 2000 and 10, respectively.•Characterization of the thermal field for the new parameters simulated.•A new feature in the temperature fluctuation never observed before was obtained: the near-wall maximum does no increase with the Reynolds number for sufficiently high Prandtl numbers.•New scalings of the conductive sublayer and the Nusselt number are proposed. A new set of DNS of a thermal channel flow have been conducted for friction Reynolds and Prandtl numbers up to 2000 and 10, respectively, reaching the Prandtl number of water, 7, for new Reynolds numbers, never simulated before. The Mixed Boundary Condition has been used as the thermal boundary condition. A new scaling of the thickness of the conductive sublayer is presented for medium–high Prandtl number values. The maximum of the intensity of the thermal field does not increase with the Reynolds number for the highest Prandtl numbers. This entails a good scaling near the wall of the viscous diffusion and the dissipation terms in the budgets of the temperature variance. The Nusselt number shows a power function behaviour with respect to the Prandtl number in a certain range of the friction Péclet number. Finally, the turbulent Prandtl number presents an increase near the wall for highest Prandtl numbers due to the reduction of the thermal eddy diffusivity. The statistics of all simulations can be downloaded from the web page of our group: http://personales.upv.es/serhocal/.