  We present a novel approach to the treatment of thermal fluctuations in the
(3+1)-D viscous hydrodynamic simulation MUSIC. The phenomenological impact of
thermal fluctuations on hadronic observables is investigated using the
IP-Glasma + hydrodynamics + hadronic cascade hybrid approach. The anisotropic
flow observed in heavy-ion collision experiments is mostly attributed to the
hydrodynamic response to the event-by-event collision geometry and to the
sub-nucleon quantum fluctuations. However, hydrodynamic fluctuations are
present during the dynamical evolution of the Quark Gluon Plasma (QGP) and are
quantified by the fluctuation-dissipation theorem. They can leave their imprint
on final-state observables. By analyzing the thermal noise mode-by-mode, we
provide a consistent scheme of treating these fluctuations as the source terms
for hydrodynamic fields. These source terms are then evolved together with
hydrodynamic equations of motion. Such a treatment captures the
non-perturbative nature of the evolution for these thermal fluctuations.
