Flow Structure Generation by Multiple Jets in Supersonic Cross-Flow

Authors: Semlitsch, B., Mihaescu, M, Fuchs, L.F., Gutmark, E.
Document Type: Conference
Pubstate: Published
Journal: Proc. of the Int. Conf. on Jets, Wakes and Separated Flows, ICJWSF-2013
Year: 2013


The flow structure generation by multiple jets impinging a supersonic crossflow in the divergent section of a Convergent-Divergent (C-D) duct is investigated using compressible Large Eddy Simulations (LES). The super- sonic flow-field in the C-D duct is mainly characterized by the evolving shock-structure. The effect of increasing the compressible jet to crossflow velocity ratio R to the generation of flow structures and the ability to modify the shock-pattern in the duct was studied. Traversing R, the shock-pattern can be significantly altered. This paper demonstrates that for close located jets in cross- flow the vortical structures generated by the jets can interact and give rise to vortical structures in the inter- space plane between the jets. The spectra for different probes are shown illustrating the characteristic flow fre- quencies. For all simulated cases the spectra show peaks for a defined Strouhal-number of 0.5. The jets choke in the crossflow above an R of about 0.65, which results in a faster disruption of the coherent flow structures in- duced by the jets. The flow field is analyzed using Proper Orthogonal Decomposition (POD).