Experimental study of a lenticular jet.

Area of Science:

• Fluid Dynamics
• Aerospace Engineering
• Combustion Science

Background:

• Non-circular jets, including elliptic and rectangular shapes, enhance mixing and combustion stability.
• Sharp-cornered jets promote small-scale mixing and vortex ring deformation.
• A combined geometry for enhanced large- and small-scale mixing was previously unstudied.

Purpose of the Study:

• To experimentally characterize the flow behavior of a novel lenticular jet.
• To compare the lenticular jet's mixing and entrainment to circular and other non-circular jets.
• To investigate the specific effect of sharp corners on jet dynamics using lenticular and elliptic jet comparison.

Main Methods:

• Experimental fluid dynamics techniques were employed for jet characterization.
• Proper Orthogonal Decomposition (POD) analysis was used to identify coherent structures.
• Comparison with existing data for circular, elliptic, and other non-circular jets.

Main Results:

• The lenticular jet exhibits higher entrainment and mixing than a standard round jet.
• Mixing and entrainment are comparable to other studied non-circular jet geometries.
• Sharp corners along the major axis of the lenticular jet lead to lower spread rate, faster turbulence breakdown, increased exit turbulence, and anisotropic centerline turbulence compared to an elliptic jet.

Conclusions:

• The lenticular jet successfully combines enhanced large- and small-scale mixing characteristics.
• Sharp corners significantly influence turbulence dynamics along the jet's major axis.
• This geometry offers potential for improved mixing applications in combustion and other fields.