Appendix E: Component Reference

The PHS framework is object‑oriented. Key classes:

• Port – effort, flow, connections. For fluid ports, effort = pressure, flow = mass flow rate.
• Connection – binds two ports: effort equality, flow sum zero. Resolved at assembly time.
• Component – abstract base with ports, state, energy computation.
• Pipe1DNonlinear – staggered Euler pipe. Primary state arrays: double[] m (mass), p_mom (momentum), E_tot (total energy) per cell. Geometry: cellArea, faceArea, dx. TVD flux limiter, boundary ports. Contains internal physical dissipation (friction, heat transfer) via source terms and R matrix.
• Volume0D – mass + internal energy, ideal gas.
• Cylinder – extends Volume0D, adds piston kinematics, Wiebe combustion, valve orifices, knock.
• Orifice – static resistive element implementing the compressible orifice flow model (valve). Stores no state; dissipates energy.
• JunctionT, JunctionX, JunctionH – 0‑junctions (common pressure) enforcing pressure equality and mass flow conservation via Lagrange multipliers.
• EffortSource – prescribed pressure (e.g., atmosphere). Equation: \(p - p_{\text{prescribed}} = 0\).
• FlowSource – prescribed mass flow (e.g., forced induction). Equation: \(\dot{m} - \dot{m}_{\text{prescribed}} = 0\).
• FfowcsWilliamsHawkings – receives exit flow/force, outputs radiated pressure.
• OutdoorReverb – ground echo + FDN.
• PHSWorld – assembles system, solves implicit midpoint via Newton‑Krylov.