Attempting to generate sound, and set cells automatically

2026-05-02 23:26:52 +02:00
parent 2c338ad7d9
commit a262410616
16 changed files with 442 additions and 285 deletions
--- a/Scenarios/Simulation.cs
+++ b/Scenarios/Simulation.cs
@@ -0,0 +1,93 @@
+using FluidSim.Audio;
+using FluidSim.Components;
+using FluidSim.Core;
+using FluidSim.Utilities;
+
+namespace FluidSim.Scenarios
+{
+    public static class Simulation
+    {
+        private static Solver solver;
+        private static Volume0D cavity, ambient;
+        private static Pipe1D neck;
+        private static Connection connNeckCavity, connNeckAmbient;
+        private static int stepCount;
+        private static double time;
+        private static double dt;
+
+        public static void Initialize(int sampleRate)
+        {
+            dt = 1.0 / sampleRate;
+
+            // --- Cavity (the “bottle”) ---
+            double V_cav = 1.0 * Units.L;                 // 1 litre
+            cavity = new Volume0D(V_cav, 10 * Units.atm, Units.Celsius(20), sampleRate);
+
+            // --- Ambient (a huge “room”) ---
+            double V_amb = 1000.0;                        // 1000 m³ ≈ constant pressure
+            ambient = new Volume0D(V_amb, 1.0 * Units.atm, Units.Celsius(20), sampleRate);
+
+            // --- Neck (short pipe) ---
+            double length_neck = 80.0 * Units.mm;
+            double diam_neck = 10 * Units.mm;
+            double area_neck = Units.AreaFromRadius(diam_neck, Units.mm);                             // few cells enough for a short neck
+            neck = new Pipe1D(length_neck, area_neck, sampleRate);
+            neck.SetUniformState(ambient.Density, 0.0, ambient.Pressure);
+            neck.FrictionFactor = 0.02;                    // slight damping
+
+            // --- Connections ---
+            // Cavity-to-neck (full area)
+            connNeckCavity = new Connection(cavity.Port, neck.PortA)
+            {
+                Area = area_neck,
+                DischargeCoefficient = 1.0,
+                Gamma = 1.4
+            };
+            // Neck-to-ambient (SoundConnection to capture the radiated tone)
+            connNeckAmbient = new SoundConnection(neck.PortB, ambient.Port)
+            {
+                Area = area_neck,
+                DischargeCoefficient = 1.0,
+                Gamma = 1.4
+            };
+
+            // --- Solver ---
+            solver = new Solver();
+            solver.AddVolume(cavity);
+            solver.AddVolume(ambient);
+            solver.AddPipe(neck);
+            solver.AddConnection(connNeckCavity);
+            solver.AddConnection(connNeckAmbient);
+
+            // --- Sound tuning ---
+            SoundProcessor.MaxDeltaP = 0.1f * (float)Units.atm; // small Δp expected
+            SoundProcessor.MaxArea = (float)area_neck;
+            SoundProcessor.MaxVelocity = 343f;
+            SoundProcessor.ReferenceDensity = 1.2f;
+            SoundProcessor.ReferenceSpeedOfSound = 343f;
+            SoundProcessor.Gain = 10.0f;  // amplify because Δp is small
+        }
+
+        public static float Process()
+        {
+            solver.Step();
+            time += dt;
+            stepCount++;
+            Log();
+            return solver.LastSample;
+        }
+
+        public static void Log()
+        {
+            if (stepCount <= 200 || stepCount % (int)(0.5 / dt) == 0)
+            {
+                Console.WriteLine(
+                    $"t = {time * 1e3:F3} ms  " +
+                    $"Sample = {solver.LastSample:F6},  " +
+                    $"P_cav = {cavity.Pressure / 1e5:F6} bar,  " +
+                    $"flow_cav = {cavity.Port.MassFlowRate / 1e3:F4} g/s,  " +
+                    $"flow_neck = {neck.PortB.MassFlowRate * 1e3:F4} g/s");
+            }
+        }
+    }
+}