Numerical simulations of flow modification of supersonic rectangular jets

Numerical simulations help in explaining the role of paddles in enhancing the acoustic noise and mixing of supersonic rectangular jets. Paddles strengthen a periodic flapping mode in the minor axis direction. The FAST3D program, using flux-corrected transport algorithms and the virtual-cell embedding technique, performs the simulations. The flapping frequency estimations involve pitot pressure distributions and Fourier analysis. The thrust loss caused by the paddles agrees well with the experimentally determined value.