No abstract

The integral energy method has been used to study the nonlinear interactions of the large-scale coherent structure in a spatially developing round jet. The streamwise development of a jet is obtained in terms of the mean flow shear-layer momentum thickness, the wave-mode kinetic energy and the wave-mode phase angle. With the energy method, a system of partial differential equations is reduced to a system of ordinary differential equations. The nonlinear differential equations are solved with initial conditions which are given at the nozzle exit. It is shown that the initial wave-mode energy densities as well as the initial phase angles play a significant role in the streamwise evolution of the large-scale coherent wave modes and the mean flow.

The i n t e g r a l energy method has been used i n o r d e r t o study t h e n o n l i n e a r i n t e r a c t i o n s of t h e l a r g e -s c a l e coherent s t r u c t u r e i n a s p a t i a l l y developing round jet. The streamwise development of a j e t i s o b t a i n e d i n terms of t h e mean flow s h e a r l a y e r momentum t h i c k n e s s , t h e wave mode k i n e t i c energy and t h e wave mode phase a n g l e . I t i s shown t h a t t h e n o n l i n e a r i n t e r a c t i o n between wave modes i s dependent on t h e wave mode phase a n g l e s .