Modelling the Accelerated Expansion of the Universe

This preprint presents a phenomenological numerical model investigating whether gravitational interaction originating outside the observable Universe can account for the additional expansion rate of the Universe. Model parameters are determined by numerical optimization to reproduce a target value of the cosmological constant Λ. The corresponding Hubble parameter H₀ is calculated from the resulting expansion term. The numerical behavior of configurations containing different numbers of external gravitational sources is investigated with respect to stability, repeatability, and parameter sensitivity.