refactoring (broken right now)

2026-05-06 15:24:39 +02:00
parent bc4e077924
commit bc0df51ddb
25 changed files with 1184 additions and 1983 deletions
--- a/Core/OpenEndLink.cs
+++ b/Core/OpenEndLink.cs
@@ -0,0 +1,123 @@
+using System;
+using FluidSim.Components;
+
+namespace FluidSim.Core
+{
+    /// <summary>
+    /// Characteristic open‑end boundary condition.
+    /// For subsonic outflow the outgoing Riemann invariant is conserved,
+    /// and the ghost pressure is set to the prescribed ambient value.
+    /// </summary>
+    public class OpenEndLink
+    {
+        public Pipe1D Pipe { get; }
+        public bool IsLeftEnd { get; }
+        public double AmbientPressure { get; set; } = 101325.0;
+        public double Gamma { get; set; } = 1.4;
+
+        // Last resolved state (for audio / monitoring)
+        public double LastMassFlowRate { get; private set; }
+        public double LastFaceDensity { get; private set; }
+        public double LastFaceVelocity { get; private set; }
+        public double LastFacePressure { get; private set; }
+
+        public OpenEndLink(Pipe1D pipe, bool isLeftEnd)
+        {
+            Pipe = pipe ?? throw new ArgumentNullException(nameof(pipe));
+            IsLeftEnd = isLeftEnd;
+        }
+
+        /// <summary>
+        /// Compute the ghost state and mass flow for one sub‑step.
+        /// </summary>
+        public void Resolve(double dtSub)
+        {
+            (double rhoInt, double uInt, double pInt) = IsLeftEnd
+                ? Pipe.GetInteriorStateLeft()
+                : Pipe.GetInteriorStateRight();
+
+            double gamma = Gamma;
+            double gm1 = gamma - 1.0;
+            double cInt = Math.Sqrt(gamma * pInt / Math.Max(rhoInt, 1e-12));
+            double pAmb = AmbientPressure;
+
+            double rhoGhost, uGhost, pGhost;
+            double mdot;
+
+            if (IsLeftEnd)
+            {
+                // Left end: outgoing invariant is J- = u - 2c/(γ-1)
+                double J_minus = uInt - 2.0 * cInt / gm1;
+
+                if (uInt <= -cInt) // supersonic inflow (all info from outside)
+                {
+                    // Simple reservoir model – use ambient density and temperature 300 K
+                    rhoGhost = pAmb / (287.0 * 300.0);
+                    uGhost = uInt;   // keep interior velocity (should be supersonic inward)
+                    pGhost = pAmb;
+                }
+                else if (uInt < 0) // subsonic inflow
+                {
+                    double rhoAmb = pAmb / (287.0 * 300.0);
+                    double cAmb = Math.Sqrt(gamma * pAmb / rhoAmb);
+                    uGhost = J_minus + 2.0 * cAmb / gm1;
+                    rhoGhost = rhoAmb;
+                    pGhost = pAmb;
+                }
+                else // subsonic outflow (uInt >= 0)
+                {
+                    double s = pInt / Math.Pow(rhoInt, gamma);
+                    rhoGhost = Math.Pow(pAmb / s, 1.0 / gamma);
+                    double cGhost = Math.Sqrt(gamma * pAmb / rhoGhost);
+                    uGhost = J_minus + 2.0 * cGhost / gm1;
+                    if (uGhost < 0) uGhost = 0;
+                    pGhost = pAmb;
+                }
+            }
+            else // Right end
+            {
+                // Right end: outgoing invariant is J+ = u + 2c/(γ-1)
+                double J_plus = uInt + 2.0 * cInt / gm1;
+
+                if (uInt >= cInt) // supersonic outflow
+                {
+                    rhoGhost = rhoInt;
+                    uGhost = uInt;
+                    pGhost = pInt;
+                }
+                else if (uInt >= 0) // subsonic outflow
+                {
+                    double s = pInt / Math.Pow(rhoInt, gamma);
+                    rhoGhost = Math.Pow(pAmb / s, 1.0 / gamma);
+                    double cGhost = Math.Sqrt(gamma * pAmb / rhoGhost);
+                    uGhost = J_plus - 2.0 * cGhost / gm1;
+                    if (uGhost < 0) uGhost = 0;
+                    pGhost = pAmb;
+                }
+                else // subsonic inflow (uInt < 0)
+                {
+                    double rhoAmb = pAmb / (287.0 * 300.0);
+                    double cAmb = Math.Sqrt(gamma * pAmb / rhoAmb);
+                    uGhost = J_plus - 2.0 * cAmb / gm1;
+                    rhoGhost = rhoAmb;
+                    pGhost = pAmb;
+                }
+            }
+
+            // Apply ghost to pipe
+            if (IsLeftEnd)
+                Pipe.SetGhostLeft(rhoGhost, uGhost, pGhost);
+            else
+                Pipe.SetGhostRight(rhoGhost, uGhost, pGhost);
+
+            // Mass flow (positive = out of pipe)
+            double area = Pipe.Area;
+            mdot = rhoGhost * uGhost * area;
+            if (IsLeftEnd) mdot = -mdot;   // positive u into pipe, so out of pipe is negative u
+            LastMassFlowRate = mdot;
+            LastFaceDensity = rhoGhost;
+            LastFaceVelocity = uGhost;
+            LastFacePressure = pGhost;
+        }
+    }
+}