‘Fuel-flexible’ gas turbines will be required over the next 20 years at least. However, this contrasts with recent experiences of
global operators who report increasing emissions and difficult combustion dynamics with even moderate variations in the fuel
supply. Swirl stabilized combustion, being the most widely spread technology to control combustion in gas turbines, will be a
technology needed for dynamic stabilization of the flow field. However, the features of the recirculation zone are highly complex,
three dimensional and time dependent, depending on a variety of parameters. A high momentum flow region inherent to swirling
flows has attracted the attention of several groups interested in blowoff and stretch flame phenomena. Therefore, this study
focuses on experimental results obtained to characterise the relation between the central recirculation zone and the high momentum
flow region under moderate swirl levels using a well-studied tangential swirl burner for power generation applications. As
to be expected the recirculation zone and the high momentum flow region rotate together about the central axis. Moreover, the
interaction between them produces high, intense local velocities. This region of High Momentum (shearing flow) also presents a
complex geometry that seems to be based on the geometrical features of the burner, different to previous findings on the burner
where the system was thought to have a unique shearing flow region. The high three dimensional interaction of these structure is
confirmed at the point where the precessing vortex core losses its strength