| The main clue of the paper was the development of high accuracy WENO schemes, applying the high accuracy LES method to solve the problems in supersonic turbulent flow, mixing and combustion.First the accuracy and dissipative properties of the 7/9th order WENO schemes was tested and its ability of capturing turbulent vortex, shock, and frequency was analyzed. With the improvement of accuracy, schemes' ability of capturing turbulent vortex, shock, and frequency was stronger. A hybrid scheme based on density to judge smoothness of flow was developed. The 6 order central difference scheme was used to solve the flow field in the smooth region, and the 5 order WENO was used near the discontinuity. The hybrid scheme with high accuracy, low dissipation and high efficiency properties, was suitable to simulate the flow field structure which was complex, like supersonic boundary layer or mixing layer.Instantaneous structure of strut's wakes was observed using PIV and NPLS technology, and the impacts of different Mach numbers and turbulent shear layer for reattachment shock and large scale crosswise vortexs were compared. The transition process of downstream wakes simulated based on high order central difference-WENO hybrid scheme, and it was concluded that the reattachment shock was the factor of inducing transition.Mixing mechanism and self-ignition phenomenon of supersonic jet were studied using LES method based on high order WENO schemes. The instability of backflow region in upstream of the jet induced large scale of turbulent eddies which promoted the mixing process between jet and crossflow accompanyed with reverse streamwise vortices in the downstream. The high total temperature transverse jet problem based on Ben-Yakar's work focusd on turbulent vortex's evolution of space-time in the flow field, discovering that the ignition of high temperature region in downstream of the bow shock was the mechanism to maintain stability of flame. |
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