Abstract
Thee owpatternsofaswirlingjetsubjecttotheine uencesofvariouscentralblockagesarestudiedexperimentally via the smoke-wire e ow visualization method. Details of the observed e ow structures are described and discussed. Thee owstructuresdisplay multiplemodes,depending on theblockageratio and swirlnumber. When theblockage ratio is less than about 0.1, swirling wake, vortex breakdown, and three-dimensional vortex shedding are observed for different ranges of swirl number. When the blockage ratio is greater than about 0.1, the bluff-body effect becomes signie cant. In this case, a pair of counter-rotating vortex rings and a central swirling jet characterize the e owe eld. Axisymmetric vortex breakdown and three-dimensional vortex shedding may appear on the central swirling jetwhen theswirlnumberorblockageratio islargerthan critical values.Somecharacteristicquantities of thee owe eld aremeasuredandcorrelated,includingthefreeseparationlines,recirculationlengths,andfrequencies of the vortex shedding.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
