“Investigation of Rectangular Jet Issuing From a Varying Cross-Section Nozzle”

Publication Type:
S. Sengupta, L. Agostini, and D. Gaitonde
Year Published:
A Large Eddy Simulation based investigation is performed on a rectangular Mach 0.226 jet to examine theeffect of differential entrainment along the minor and major axes. The nozzle has a circular cross-section atthe inlet and a 2:1 aspect ratio rectangular cross-section (5.3848cm equivalent hydraulic diameter) at the exit.The Reynolds number of the flow is 73,242. The streamwise distribution of both mean and rms axial velocityfluctuations along the jet centerline agree with available experimental data. Q-criterion iso-levels confirmthe existence of large hairpin like vortices, which initially are dominant along the major axis but furtherdownstream, appear along the minor axis as well. The integral scales of these structures are investigatedthrough their pressure footprints along the minor axis, major axis and corner. To highlight the influence ofdifferent frequency ranges, the velocity field at the core collapse location is first decomposed using EmpiricalMode Decomposition (EMD). The spectrum in these different ranges is then correlated with observations alongrepresentative lip-line at the major and minor axes and the corner. The presence of the large scale structurescorresponding to low frequency ranges is predominant along the corner compared to major and minor axes.The correlations provide information on the connections between the structures and local times scales. Themajor components of low frequency structures in the propagated signal occur between St = 0.05 and St = 0.3
Conference Name:
54th AIAA Aerospace Sciences Meeting
Conference Location:
San Diego, California
Other Numbers:
Refereed Designation:
Date Published: