Effect of wall temperature in supersonic turbulent boundary layers: A numerical study. (February 2015)

• Record Type: Journal Article
• Authors: Hadjadj, A.; Ben-Nasr, O.; Shadloo, M.S.; Chaudhuri, A.
• Is Part Of: International journal of heat and mass transfer. Volume 81(2015:Feb.)
• Page Start: 426
• Page End: 438
• Publication Date: 2015-02
• Subjects: Supersonic turbulent boundary layer (STBL) -- Wall heat transfer -- Large-Eddy Simulation (LES) -- Morkovin's hypothesis; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2014.10.025
• Languages: English
• ISSNs: 0017-9310

Abstract

Abstract: The present work is dedicated to the numerical study of statistical characteristics of spatially-evolving supersonic turbulent boundary layers (STBL) with cooled walls. Large-Eddy Simulations (LESs) are performed to gain further insight into the role of wall temperature on the mean and fluctuating-flow properties of STBL. The velocity fluctuations, which are scaled according to the Morkovin's hypothesis, have shown acceptable agreement with available experimental and DNS results of literature. However, the van Driest transformed skin friction C f inc lies below the incompressible theoretical curves as a function of Re θ inc for cold STBL, whereas compressible skin friction is found to be relatively higher for cold wall boundary layers than adiabatic boundary layers. The variation of total shear stress remains unaffected throughout the boundary layer for 0.5 ⩽ T w / T r ⩽ 1 . The total temperature fluctuations are non-negligible for cold cases and surface cooling changes the near-wall turbulent structures. Additionally, the streamwise velocity and temperature fluctuations for the coldest isothermal STBL case are strongly correlated compared to the anti-correlation behavior of the adiabatic STBL in the near-wall region ( y + ≈ 9 ). Furthermore, the pressure fluctuations are found to be non-negligible for cooled boundary layers and a positive correlation between pressure and density fluctuations are observed in the log-layer. These tendencies have also been verified through a detailed statistical analysis of the unsteady flow-field.