U.S. Patent 6,666,016

What it is ...

Operating conditions


Round-jet experiments

2D-jet experiments

Twin-fluid atomization

Investigation of fundamental physics






A subtle change in the nozzle shape of the outer stream causes the flow to mix more vigorously.  This phenomenon is exploited to enhance mixing in a variety of applications

meaf_intro.jpg (70056 bytes)

The phenomenon exemplified by these images involves axial injection of a gas at special conditions that lead to:

  • Enhanced mixing of the gas itself.   This is called Jet Self Excitation (JSE).  See an example.

  • Enhanced mixing of an arbitrary flow (gas or liquid) adjacent to or surrounded by the unstable gas.  This is called  Mixing Enhancement via Secondary Parallel Injection  (MESPI).   See an example.

The mixing enhancement mechanism has been traced to instabiliy of the shock system in supersonic nozzle flow separation.

Potential applications

  • Exhaust of aircraft engines for thermal signature reduction. 
  • Ejectors for aircraft engines and for pumps. 
  • Fuel injectors for automotive, aircraft, and scramjet engines. 
  • Gas mixing in chemical lasers. 
  • Spray injectors for materials processing and coating applications. 

Key Publications:

Papamoschou, D., "Mixing Enhancement Using Axial Flow," AIAA-2000-0093 (PDF).

Murakami, E. and Papamoschou, D., "Experiments on Mixing Enhancement in Dual-Stream Jets," (PDF).

Papamoschou, D., Dixon, T.T, and Nishi, K.A.,  "Mean Flow of Multistream Rectangular Jets under Normal and Mixing-Enhancement Conditions,"   AIAA-2004-0919  (PDF).

Debiasi, M., Dhanabalan, S. S., Tsai, H. M., and Papamoschou, D., “Mixing Enhancement of High-Bypass Turbofan Exhausts via Contouring of Fan Nozzle”, AIAA Paper 2007-4497 (PDF).

Xiao, Q., Tsai, H.M., and Papamoschou, D., "Numerical Investigation of Supersonic Nozzle Flow Separation," AIAA Journal, Vol. 45, No.3, 2007, pp. 532-541 (PDF).

Xiao, Q., Tsai, H.M., and Papamoschou, D., and Johnson, A.,  "Experimental and Numerical Study of Jet Mixing from a Shock-Containing Nozzle," Journal of Propulsion and Power, Vol. 25, No.3, 2009, pp. 688-696.(PDF)

Papamoschou, D., Zill, A., and Johnson, A.,   "Supersonic Flow Separation in Planar Nozzles, "  Journal of Shock Waves, Vol.19, No.3, 2009, pp. 171-183 (PDF). 

Johnson, A.D., and Papamoschou, D., "Instability of Shock-Induced Nozzle Flow Separation," Physics of Fluids, Vo.22, Article 016102, 2010. (PDF).



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