Three-dimensional vortex method simulations were performed of a forced, impulsively started round jet. The viscous diffusion of vorticity was represented by a core spreading model which approximates the growth of the rectilinear viscous vortex tube. The jet was sinusoidally forced by helical or multiple disturbances to clarify evolution of vortical structures. The multiple disturbance is a combination of two helical disturbances of the same mode and amplitude, rotating in the opposite directions. The multiple disturbance of mode 2 was found to most enhance both the growth rate and generation of small-scale vortices among the other disturbances. A turbulence core spreading model in the spirit of Smagorinsky sub-grid scale viscosity (Leonard and Chua 1989) was also studied. The linear combination of the two models can be interpreted as a Lagrangian turbulence model which includes Reynolds-number effects.
|Title of host publication||Proceedings of the 1999 3rd ASME/JSME Joint Fluids Engineering Conference, FEDSM'99, San Francisco, California, USA, 18-23 July 1999 (CD-ROM)|
|Publisher||American Society of Mechanical Engineers|
|Number of pages||1|
|Publication status||Published - 1999 Dec 1|
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Environmental Science(all)