FQ Graviton Fluid Dynamics: Cosmic Macro‑Vortex, Redshift Mechanism and Black Hole Accretion‑Jet Picture

While the Λ‑CDM standard cosmological model achieves considerable success in observational fitting, it still faces unresolved fundamental problems including the unknown physical nature of dark matter and dark energy, the Hubble tension, and the anisotropy of galactic recession velocities. Based on two previous phenomenological studies — the “rotating‑fly‑disk” global‑rotating universe model and the modified‑gravity model with the field‑excitation coefficient η for galactic rotation curves — this paper establishes the ontological framework of FQ graviton‑fluid dynamics. Within this framework, gravity is interpreted as a blocking‑pressure‑difference momentum‑transfer effect originating from the omnipresent graviton fluid. A strict distinction is drawn between local‑perturbation propagation inside the medium and large‑scale collective convection of fluid‑medium elements. Illustrated by the wheel‑conveyor‑belt heuristic analogy: local electromagnetic and gravitational perturbations obey the speed‑of‑light limit relative to local fluid elements; by contrast, the collective‑convection velocity of medium elements within the cosmic‑scale graviton‑fluid macro‑vortex is not bounded by this local speed‑of‑light constraint. Galactic redshift arises from genuine relative motion induced by fluid‑vortex dragging, providing a physical mechanism for galactic recession and replacing the dark‑energy hypothesis. The phenomenological field‑excitation coefficient η receives a fluid‑dynamics interpretation: η characterizes the effective blocking cross‑section of nucleon‑density‑dependent matter acting upon the graviton fluid. Compact celestial bodies (black holes) produce a saturated‑blocking “fluid‑reef” effect, which reproduces galactic rotation curves without invoking dark‑matter particles. Further, a heuristic conjecture for material decomposition and shunting inside black‑hole accretion regions is proposed: a black‑hole core is not composed of graviton fluid, but ultra‑dense nuclear remnants compressed by graviton‑fluid pressure differences. Infalling matter mostly disintegrates within the accretion region outside the event horizon. Light‑particle fragments form relativistic jets along low‑pressure bipolar channels of the macro‑vortex, while a small population of heavy atomic nuclei becomes entrained into jets via turbulence. This paper inherits established observational predictions: redshift‑deviation tests for CBRF polar‑sky fields from LSST surveys, plus statistical tests of galaxy‑spin axes from FAST neutral‑hydrogen surveys. Falsification criteria for the black‑hole‑jet conjecture are explicitly laid out. Model‑intrinsic limitations are objectively catalogued, and a roadmap for future numerical‑simulation and observational validation is provided.