Published 6 issues per year
ISSN Print: 2152-5102
ISSN Online: 2152-5110
Indexed in
Passive Control of Circular Jet Spread-Rates with Axially Splined Nozzles
ABSTRACT
Experimental measurements for the axial development of streamwise velocity and turbulence distributions in the near field of free circular jets issued from splined nozzles are presented. Results include the axial distribution of mean flow and turbulence related quantities of a free circular jet with different nozzle exit conditions. Hot-wire data reveal interesting characteristics on jet spread-rate, shear layer width, and momentum thickness. Observed jet-characteristics are explained on the basis of the velocity and turbulence profiles measured at the nozzle exit. Axial splines at the circumference of the jet nozzle enhance turbulence at the jet circumference boundary layer without significantly changing the nozzle core flow. The boundary layer at the splined jet nozzle exit, i.e., at the start of the free shear layer, increases in thickness due to an increase in turbulence mixing. The addition of splines reduces the jet spread-rate and the growth of shear layer width. It is also observed that splines cause turbulence suppression at downstream locations and this method can be used as a passive control of jets.