  We investigate the turbulent properties of a confined driven-dissipative
polariton quantum fluid after a pulsed excitation. Using numerical simulations,
we provide insight into the vortex clustering processes that emerge during the
relaxation dynamics of the initially injected vortex cloud. A confrontation
between conservative and non-conservative dynamics reveals that the onset of
clusterization strongly depends on the interplay between the different
characteristic system lengths and time scales at stake, with an additional time
scale due to dissipation in the non-conservative case. Quantification of the
clustering observables allows us to numerically characterize the optimal
conditions for observing Onsager condensation in decaying polariton systems,
demonstrating its experimental reachability under pulse excitation. These
findings hold significance for exploring the onset of turbulent dynamics in
open systems, spanning both classical and quantum domains.
