Martini Spin-Filament Coupling Model: A Numerical Framework for Falsifiable Predictions of Black Hole Spin Alignment in Cosmic Filaments

We introduce the Martini Spin-Filament Coupling Model (msfcm), a phenomenological framework in which cosmic filaments exert a viscous drag torque on the intrinsic spin vectors of black holes embedded within them. The coupling strength is governed by a dimensionless viscosity parameter τ , which we interpret as proportional to the velocity dispersion σ of the host filament via the calibration relation τ = τc (σ/σref), with τc = 0.15 and σref = 200 km s−1 .