neqsim-cfd-coupling

Flash the fluid in NeqSim, call fluid_state_from_neqsim to extract density and viscosity, derive boundary conditions with derive_boundary_conditions, then write the case with OpenFoamCase.write. The case runs automatically when OpenFOAM is installed, otherwise the commands to run it elsewhere are returned.

Use derive_multiphase_conditions, which computes Weber, Froude, and Stokes numbers plus the maximum stable droplet size from one flash. It recommends vof for resolvable interfaces like stratified or slug flow, lagrangian for dilute mists, and euler_euler for dense dispersed phases.

Yes, both are optional. Without NeqSim you supply the fluid state directly as a FluidState object; without OpenFOAM the case is still written to disk and the commands needed to run it elsewhere are returned.

Transport properties return as zero unless initProperties() is called on the NeqSim system after the flash. The fluid_state_from_neqsim function invokes it automatically, but reading properties directly from a phase without it produces an absurd Reynolds number.

Avoid steady RANS for tonal noise diagnosis, fatigue, or erosion questions, because it smooths the fluctuations those questions depend on. For tonal aeroacoustics, call assess_aeroacoustic_readiness first; it fails closed unless geometry, synchronized spectra, and acoustic boundaries are available.

The skill generates steady single-phase RANS and transient VOF cases only; Lagrangian and Euler-Euler models are recommended but not written. Phase change, cavitation, combustion, conjugate heat transfer, and temperature fields are out of scope, and fluid properties are frozen at the inlet flash.