Reynolds Number Effects on Shock Boundary Layer Interaction Over an Axisymmetric Surface

Shock-wave/boundary-layerinteractions(SBLIs)areadistinctiveattributeofhigh-speed flows. Thecurvatureoftheinteractionsurfaceofanaxisymmetricbodyonwhichanoblique shock impinges and interacts with a supersonic boundary layer profoundly affects the flow topology anddynamics overandaroundthebody. This studyinvestigatesSBLIs overathree- dimensionalrightcircularcylinderatMach2usinghigh-fidelityimplicitlargeeddysimulations (I-LES) at Reynolds numbers of 35,800 (laminar) and 100,000 (turbulent). The impinging oblique shock induces a complex flow separation, including both open and closed types, and a conical three-dimensional reattachment shock, with vortex dynamics changing spatially andcross-flowinfluencepost-separationduetosurfacecurvature,adversepressuregradients, Reynoldsnumbereffects,andinflowturbulence. Detailedanalysesofwallpressure,skinfriction, andvortextopology,includingprimary,secondary,andtertiaryvortices,revealedthatturbulent interactiondelaysseparation,shortenstheseparationbubble,enhancesmixing,andproduces three-dimensional vortex systems. Wall-pressure spectra reveal broadband low-frequency unsteadiness linked to global separation dynamics and bubble breathing. Distinct peaks correspondtoshear-layerflappingandreattachment,K-Hshedding,andvortexroll-up. Higher frequenciesreflectvortexbreakdownandwaketurbulencepost-reattachment. Theseinteractions arerelevanttoforebodyaerodynamics,enginenacelles,andstore-carriageconfigurationsin supersonicflight,whereunsteadyshockmotionsinducefluctuatingsurfacepressuresthatexcite structuralvibrations,diminishaerodynamicefficiency, and degrade vehicle performance.