Finite-rate chemistry effects in turbulent hypersonic boundary layers: A direct numerical simulation study
Article dans une revue avec comité de lecture
The influence of high-enthalpy effects on hypersonic turbulent boundary layers is investigated by means of direct numerical simulations (DNS). A quasiadiabatic flat-plate air flow at free-stream Mach number equal to 10 is simulated up to fully developed turbulent conditions using a five-species, chemically reacting model. A companion DNS based on a frozen-chemistry assumption is also carried out, in order to isolate the effect of finite-rate chemical reactions and assess their influence on turbulent quantities. In order to reduce uncertainties associated with turbulence generation at the inlet of the computational domain, both simulations are initiated in the laminar flow region and the flow is let to evolve up to the fully turbulent regime. Modal forcing by means of localized suction and blowing is used to trigger laminar-to-turbulent transition. The high temperatures reached in the near-wall region including the viscous and buffer sublayers activate significant dissociation of both oxygen and nitrogen. This modifies in turn the thermodynamic and transport properties of the reacting mixture, affecting the first-order statistics of thermodynamic quantities. Due to the endothermic nature of the chemical reactions in the forward direction, temperature and density fluctuations in the reacting layer are smaller than in the frozen-chemistry flow. However, the first- and second-order statistics of the velocity field are found to be little affected by the chemical reactions under a scaling that accounts for the modified fluid properties. We also observed that the Strong Reynolds Analogy remains well respected despite the severe hypersonic conditions and that the computed skin friction coefficient distributions match well the results of the Renard-Deck decomposition extended to compressible flows.
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Assessment of a high-order shock-capturing central-difference scheme for hypersonic turbulent flow simulations Article dans une revue avec comité de lectureSCIACOVELLI, Luca; PASSIATORE, Donatella; CINELLA, Paola; GIUSEPPE, Pascazio (Elsevier, 2021-11)High-speed turbulent flows are encountered in most space-related applications (including exploration, tourism and defense fields) and represent a subject of growing interest in the last decades. A major challenge in ...
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 ...
Communication avec acteA high-order shock-capturing finite-difference scheme for scale-resolving numerical simulations of hypersonic high-enthalpy flows, involving thermal non-equilibrium effects, is presented. The suitability of the numerical ...
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Communication avec actePASSIATORE, Donatella; SCIACOVELLI, Luca; CINNELLA, Paola; PASCAZIO, Giuseppe (3AF, Association Aéronautique et Astronautique de France, 2023-03-29)The dynamics of a shock wave impinging on a freestream-perturbed high-enthalpy boundary layer is investigated by means of direct numerical simulation. The oblique shock impacts on a cooled flat-plate boundary layer with ...