Numerical Investigation of High‑Speed Turbulent Boundary Layers of Dense Gases
Article dans une revue avec comité de lecture
High-speed turbulent boundary layers of a dense gas (PP11) and a perfect gas (air) over flat plates are investigated by means of direct numerical simulations and large eddy simulations. The thermodynamic conditions of the incoming flow are chosen to highlight dense gas effects, and laminar-to-turbulent transition is triggered by suction and blowing. In the paper, the behavior of the fully developed turbulent flow region is investigated. Due to the low characteristic Eckert number of dense gas flows ( Ec = U2 ∞∕cp,∞T∞ ), the mean velocity profiles are largely insensitive to the Mach number and very close to the incompressible case even at high speeds. Second-order velocity statistics are also weakly affected by the flow Mach number and the velocity spectra are characterized by a secondary peak in the outer region of the boundary layer because of the higher local friction Reynolds number. Despite the incompressible-like velocity and Reynolds-stress profiles, the strongly nonideal thermodynamic and transport-property behavior of the dense gas results in unconventional distributions of the fluctuating thermo-physical quantities. Specifically, density and viscosity fluctuations reach a peak close to the wall, instead of vanishing as in perfect gas flows. Additionally, dense gas boundary layers exhibit higher values of the fluctuating Mach number and velocity divergence and a larger dilatational-to-solenoidal dissipation ratio in the near-wall region, which represents a major deviation from high-Mach-number perfect gas boundary layers. Other significant deviations are represented by the more symmetric probability distributions of fluctuating quantities such as the density and velocity divergence, due to the more balanced occurrence of strong expansion and compression events.
Showing items related by title, author, creator and subject.
Article dans une revue avec comité de lectureGLOERFELT, Xavier; ROBINET, Jean-Christophe; SCIACOVELLI, Luca; CINNELLA, Paola; GRASSO, Francesco (Cambridge University Press (CUP), 2020)A study of dense-gas effects on the stability of compressible boundary-layer flows is conducted. From the laminar similarity solution, the temperature variations are small due to the high specific heat of dense gases, ...
Article dans une revue avec comité de lecturePASSIATORE, Donatella; SCIACOVELLI, Luca; CINNELLA, Paola; GIUSEPPE, Pascazio (2022-04-28)A hypersonic, spatially evolving turbulent boundary layer at Mach 12.48 with a cooled wall is analysed by means of direct numerical simulations. At the selected conditions, massive kinetic-to-internal energy conversion ...
Article dans une revue avec comité de lectureSCIACOVELLI, Luca; CINNELLA, Paola; GRASSO, Francesco (Cambridge University Press (CUP), 2017)The present paper investigates the influence of dense gases governed by complex equations of state on the dynamics of homogeneous isotropic turbulence. In particular, we investigate how differences due to the complex ...
Article dans une revue avec comité de lectureSCIACOVELLI, Luca; CINNELLA, Paola; CONTENT, C.; GRASSO, Francesco (Cambridge University Press (CUP), 2016)A detailed numerical study of the influence of dense gas effects on the large-scale dynamics of decaying homogeneous isotropic turbulence is carried out by using the van der Waals gas model. More specifically, we focus on ...
Article dans une revue avec comité de lectureSCIACOVELLI, Luca; CINNELLA, Paola; GLOERFELT, Xavier (Cambridge University Press (CUP), 2017)The influence of dense-gas effects on compressible wall-bounded turbulence is investigated by means of direct numerical simulations of supersonic turbulent channel flows. Results are obtained for PP11, a heavy fluorocarbon ...