Large-Eddy simulation of highly under-expanded hydrogen jets using a low dissipative solver

Large-eddy simulation (LES) of H 2 jets is carried out at nozzle pressure ratios 5.8 ≤ NPR ≤ 10. A low-dissipative, localized flux formulation is proposed and validated using 1D–3D reference cases. In the present under-expanded jet studies, the following numerical observations are made. (1) The proposed low-dissipative approach resolves both shocks and turbulence simultaneously. The transition to turbulence is noted to start up to ≈ 10 D earlier for under-expanded jets with low-dissipative approach in comparison to the fully dissipative flux approach. (2) A comparison of H 2 , CH 4 , and N 2 jets indicates a delayed transition to turbulence for H 2 at NPR = 6.5. (3) At all NPRs, the H 2 jet turbulence transition is delayed, but the transition shifts towards the nozzle when the NPR increases. (4) The normalized peak vorticity ( ω z D / U 1 ) values for Görtler vortices around the barrel shock boundary of H 2 jet is observed to be ≈ 4 times lower compared to representative CH 4 and N 2 jets. (5) For H 2 , Mach disk oscillation is observed and linked to the global POD modes at a Strouhal number range of S t ≈ 0 . 063 − 0 . 078 . • Density-based low-dissipative finite volume solver implemented within OpenFOAM®. • Shock capturing KT scheme locally activated at the location of strong shocks. • Taylor–Görtler instabilities in the near nozzle region evolved slowly in H 2 jets. • H 2 jets exhibit delayed turbulent transition in comparison to CH 4 and N 2 . • POD analysis revealed distinct frequencies associated with Mach disk oscillation in H 2 jets.