Open Flow Field Space Dynamical Behavior Of An Experimental Research Framework And Several Types Of Classic Flow Field Study

A novel framework of experimental studies on local and global dynamics of spatial evolutional open flows has been put forward. In mathematics, it can be boiled down to two equivalent forms of a kind of classical solutions to the general Navier-Stokes Equation of velocity fluctuations (NSE). In experiments, local dynamics, namely the contributions of the nonlinearity of NSE to the local spatial evolutions of velocity fluctuations can be revealed by the extended auto-bispectrum. It has been discovered that the nonlinearity plays the essential role in the stimulation of small-scale structures, namely turbulence generation. On the other hand, a concept termed as physical territorial attractor (PTA) has been put forward according to the property of real open flows. Spatial evolutions of open flows, subsequently, can be described by different PTAs. Global dynamics in a single PTA and in different PTAs can be studied by global relations, namely a kind of equivalent forms. The dynamics of axisymmetric free shear flows, axisymmetric variable-density jets and wakes of cylinders have been studied, to a certain extent, under this framework.