Direct Numerical Simulation of a hypersonic boundary layer in chemical non-equilibrium
Communication avec acte
The influence of high-enthalpy effects in hypersonic, spatially developing boundary layers is investigated by means of direct numerical simulations. The flow of a reacting mixture of nitrogen and oxygen over a flat plate at Mach 10, previously investigated in the literature using linear stability theory (LST), is simulated using a compu-tational domain encompassing the laminar, transitional and turbulent regimes. Transition is triggered by forcing Mack’s second mode through suction and blowing at the wall. In the laminar region, the solution matches reasonably well the locally self-similar profiles, computed under chemical non-equilibrium assumptions. Strong dissociation phenomena are observed, due to the high temperatures reached close to the (uncooled) plate surface. The transitional regime is investigated by means of modal analysis. Despite the significant chemical activity, the results confirm the classical transition scenario for high-Mach number boundary layers, for which the second-mode resonance is the main mechanism responsible for turbulent breakdown. In the turbulent region, first- and second-order statistics reveal that chemical reactions do not modify significantly dynamic quantities such as velocity and Reynolds stress profiles, but greatly affect thermal properties, due to their endothermic nature. For the configuration at hand, chemical dissociation is slower than the characteristic time-scale of the flow, and the peak of chemical activity is located in the viscous sublayer, leading to mild modifications of the turbulent field compared to a frozen-chemistry model.
Files in this item
Showing items related by title, author, creator and subject.
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 ...
Communication avec actePASSIATORE, Donatella; SCIACOVELLI, Luca; CINNELLA, Paola; PASCAZIO, Giuseppe (Council of the Aeronautical Sciences, 2022-11)A hypersonic turbulent boundary layer over a flat plate is numerically investigated. The large Mach number and temperature values in the freestream (M e = 12.48 and T e = 594.3 K, respectively) lead to a high-enthalpy ...
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 ...
Communication sans actePASSIATORE, Donatella; SCIACOVELLI, Luca; PASCAZIO, Giuseppe; CINNELLA, Paola (IUTAM, International Union of Theoretical and Applied Mechanics, 2021-08)The influence of high-temperature effects on compressible wall-bounded turbulence is investigated by means of a direct numerical simulation of a hypersonic, chemically out-of-equilibrium, turbulent boundary layer. The ...