tuff
This commit is contained in:
@@ -13,139 +13,197 @@ namespace FluidSim.Core
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private Crankshaft crankshaft;
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private EngineCylinder engineCyl;
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private Pipe1D exhaustPipe;
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private PipeVolumeConnection coupling;
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private SoundProcessor soundProcessor;
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private Pipe1D intakePipe;
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private PipeVolumeConnection couplingExhaust;
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private PipeVolumeConnection couplingIntake;
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private SoundProcessor exhaustSoundProcessor;
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private SoundProcessor intakeSoundProcessor;
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private OutdoorExhaustReverb reverb;
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private Port exitPort = new Port();
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private Port exhaustPort = new Port();
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private Port intakePort = new Port();
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private double dt;
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private double pipeArea;
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private double exhPipeArea, intPipeArea;
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private const double AmbientPressure = 101325.0;
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private double time;
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private int stepCount = 0;
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private const int LogInterval = 10000;
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private const int LogInterval = 1000;
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// Throttle 0..1
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public double Throttle { get; set; } = 0.0; // start with a light idle throttle
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// ---- Realistic combustion parameters ----
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private const double FullLoadPeakPressure = 70.0 * 101325.0; // 15 bar
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// ---- Idle speed governor ----
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private const double TargetIdleRPM = 800.0; // rad/s = RPM * π/30, we'll convert
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public double Throttle { get; set; } = 0.15;
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private const double FullLoadPeakPressure = 60.0 * Units.bar;
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public override void Initialize(int sampleRate)
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{
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dt = 1.0 / sampleRate;
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// ---- Crankshaft: inertia + friction that gives ~800 RPM at idle ----
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crankshaft = new Crankshaft(initialRPM: 600.0) // start a bit low
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// Crankshaft
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crankshaft = new Crankshaft(initialRPM: 2000.0)
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{
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Inertia = 0.005, // slightly heavier flywheel
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FrictionConstant = 0.8, // static friction
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FrictionViscous = 0.01 // viscous (linear with RPM)
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Inertia = 0.05,
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FrictionConstant = 0.5,
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FrictionViscous = 0.01
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};
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// ---- Pipe: add a tiny bit of damping to prevent unrealistic shocks ----
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double pipeLength = 2;
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double pipeRadius = 0.1;
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pipeArea = Math.PI * pipeRadius * pipeRadius;
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exhaustPipe = new Pipe1D(pipeLength, pipeArea, sampleRate, forcedCellCount: 60);
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// Exhaust pipe (longer, larger)
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double exhLength = 1;
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double exhRadius = 0.02;
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exhPipeArea = Math.PI * exhRadius * exhRadius;
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exhaustPipe = new Pipe1D(exhLength, exhPipeArea, sampleRate, forcedCellCount: 100);
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exhaustPipe.SetUniformState(1.225, 0.0, AmbientPressure);
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exhaustPipe.DampingMultiplier = 5;
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exhaustPipe.EnergyRelaxationRate = 50;
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exhaustPipe.DampingMultiplier = 0.0;
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exhaustPipe.EnergyRelaxationRate = 100.0f;
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// ---- Cylinder ----
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// Intake pipe (shorter, narrower)
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double intLength = 1;
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double intRadius = 0.01;
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intPipeArea = Math.PI * intRadius * intRadius;
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intakePipe = new Pipe1D(intLength, intPipeArea, sampleRate, forcedCellCount: 50);
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intakePipe.SetUniformState(1.225, 0.0, AmbientPressure);
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// Cylinder (starts at BDC, fresh charge)
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engineCyl = new EngineCylinder(crankshaft,
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bore: 0.065, stroke: 0.0565, compressionRatio: 10.0,
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pipeArea: pipeArea, sampleRate: sampleRate);
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bore: 0.065, stroke: 0.0565, compressionRatio: 8.0,
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exhPipeArea: exhPipeArea, intPipeArea: intPipeArea, sampleRate: sampleRate);
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engineCyl.ignition = true;
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// ---- Coupling ----
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coupling = new PipeVolumeConnection(engineCyl.Cylinder, exhaustPipe, true, orificeArea: 0.0);
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// Set crank to BDC (180°) and sync
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crankshaft.CrankAngle = Math.PI;
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crankshaft.PreviousAngle = Math.PI; // make sure this property is settable (public setter)
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// ---- Solver ----
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// Couplings
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couplingExhaust = new PipeVolumeConnection(engineCyl.Cylinder, exhaustPipe, true, orificeArea: 0.0);
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couplingIntake = new PipeVolumeConnection(engineCyl.Cylinder, intakePipe, false, orificeArea: 0.0);
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// Solver
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solver = new Solver();
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solver.SetTimeStep(dt);
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solver.AddVolume(engineCyl.Cylinder);
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solver.AddPipe(exhaustPipe);
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solver.AddConnection(coupling);
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solver.AddPipe(intakePipe);
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solver.AddConnection(couplingExhaust);
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solver.AddConnection(couplingIntake);
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solver.SetPipeBoundary(exhaustPipe, false, BoundaryType.OpenEnd, AmbientPressure);
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solver.SetPipeBoundary(intakePipe, true, BoundaryType.GhostCell); // cylinder side – left
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solver.SetPipeBoundary(intakePipe, false, BoundaryType.OpenEnd, AmbientPressure); // ambient side – right
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// ---- Sound processor (stable version) ----
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soundProcessor = new SoundProcessor(sampleRate, pipeRadius * 2);
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soundProcessor.Gain = 0.00001f;
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// Sound
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exhaustSoundProcessor = new SoundProcessor(sampleRate, exhRadius * 2);
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exhaustSoundProcessor.Gain = 0.001f;
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// ---- Reverb ----
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intakeSoundProcessor = new SoundProcessor(sampleRate, intRadius * 2);
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intakeSoundProcessor.Gain = 0.001f;
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// Reverb
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reverb = new OutdoorExhaustReverb(sampleRate);
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// Church: vast, highly reflective, bright
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reverb.DryMix = 1.0f; // always full dry signal
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reverb.EarlyMix = 0.5f; // distinct early reflections from distant walls
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reverb.TailMix = 0.9f; // huge tail, almost as loud as the dry sound
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reverb.Feedback = 0.9f; // long decay – roughly 3 s reverb time (with current delay lengths)
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reverb.DampingFreq = 6000f; // bright: high‑frequency energy stays for a long time
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reverb.MatrixCoeff = 0.5f; // default orthogonal mix
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reverb.DryMix = 1.0f;
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reverb.EarlyMix = 0.5f;
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reverb.TailMix = 0.9f;
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reverb.Feedback = 0.9f;
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reverb.DampingFreq = 6000f;
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Console.WriteLine("=== EngineScenario (Stable) ===");
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Console.WriteLine($"Crankshaft inertia: {crankshaft.Inertia}");
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Console.WriteLine($"Pipe: {pipeLength} m, fundamental: {340/(4*pipeLength):F1} Hz");
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Console.WriteLine("=== Engine with intake & cycle‑aware valves ===");
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}
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public override float Process()
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{
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// ---- RPM governor: adjust throttle to maintain idle when no user input ----
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double currentRPM = crankshaft.AngularVelocity * 60.0 / (2.0 * Math.PI);
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double throttle = Math.Clamp(Throttle, 0.05, 1.0); // never let it drop below a tiny value
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// ---- Target combustion pressure ----
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double throttle = Math.Clamp(Throttle, 0.2, 1.0);
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double targetPressure = throttle * FullLoadPeakPressure;
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engineCyl.TargetPeakPressure = targetPressure;
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// ---- Simulate one timestep ----
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engineCyl.Step(dt);
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crankshaft.Step(dt);
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coupling.OrificeArea = engineCyl.OrificeArea;
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couplingExhaust.OrificeArea = engineCyl.ExhaustOrificeArea;
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couplingIntake.OrificeArea = engineCyl.IntakeOrificeArea;
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solver.Step();
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// ---- Update exit port with safety clamps ----
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UpdateExitPort();
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UpdateExhaustPort();
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UpdateIntakePort();
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float dryExhaust = exhaustSoundProcessor.Process(exhaustPort);
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float dryIntake = intakeSoundProcessor.Process(intakePort);
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float dry = dryExhaust + dryIntake;
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// ---- Generate audio ----
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float dry = soundProcessor.Process(exitPort);
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float wet = reverb.Process(dry);
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time += dt;
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stepCount++;
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if (++stepCount % LogInterval == 0) Log();
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return wet;
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}
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private void UpdateExitPort()
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private void Log()
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{
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double rpm = crankshaft.AngularVelocity * 60.0 / (2.0 * Math.PI);
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double cycleDeg = (engineCyl.CycleAngle * 180.0 / Math.PI) % 720.0;
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string stroke = cycleDeg < 180.0 ? "Power" :
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cycleDeg < 360.0 ? "Exhaust" :
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cycleDeg < 540.0 ? "Intake" : "Compression";
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// Cylinder
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double pCyl = engineCyl.Cylinder.Pressure;
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double TCyl = engineCyl.Cylinder.Temperature;
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double VCyl = engineCyl.Cylinder.Volume;
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double mCyl = engineCyl.Cylinder.Mass;
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double exhArea = engineCyl.ExhaustOrificeArea * 1e6; // mm²
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double intArea = engineCyl.IntakeOrificeArea * 1e6; // mm²
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// Exhaust pipe
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int exhLast = exhaustPipe.GetCellCount() - 1;
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double pExhEnd = exhaustPipe.GetCellPressure(exhLast);
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double mdotExhOut = exhaustPipe.GetOpenEndMassFlow(); // positive out
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// Intake pipe
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double mdotIntIn = couplingIntake.LastMassFlowIntoVolume;
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double pIntAmbEnd = intakePort.Pressure;
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Console.WriteLine(
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$"{stepCount,8} {stroke,-11} {cycleDeg,6:F1}° " +
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$"RPM:{rpm,5:F0} " +
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$"Cyl: p={pCyl/1e5,6:F3}bar T={TCyl,6:F0}K V={VCyl*1e6,6:F0}cm³ m={mCyl*1e3,6:F6}g " +
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$"Valves: Exh={exhArea,5:F0}mm² Int={intArea,5:F0}mm² " +
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$"Intake: p_end={pIntAmbEnd/1e5,6:F3}bar mdot_in={mdotIntIn,7:F4}kg/s " +
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$"Exhaust: p_end={pExhEnd/1e5,6:F3}bar mdot_out={mdotExhOut,7:F4}kg/s");
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}
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private void UpdateExhaustPort()
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{
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int last = exhaustPipe.GetCellCount() - 1;
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double p = exhaustPipe.GetCellPressure(last);
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double rho = exhaustPipe.GetCellDensity(last);
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double vel = exhaustPipe.GetCellVelocity(last);
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// Clamp density to physically possible values
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if (rho < 0.01) rho = 0.01; // never let it approach zero
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if (rho > 50.0) rho = 50.0; // never let it become absurd
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// Clamp velocity to ± 500 m/s (safe subsonic)
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// Safety clamps
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rho = Math.Clamp(rho, 0.01, 50.0);
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vel = Math.Clamp(vel, -500.0, 500.0);
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p = Math.Clamp(p, 1e4, 2e6);
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double outflowMassFlow = rho * vel * pipeArea;
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double outflowMassFlow = rho * vel * exhPipeArea;
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// Clamp exit pressure to sensible range (0.1 – 20 bar)
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p = Math.Clamp(p, 1e4, 2e6);
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exitPort.Pressure = p;
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exitPort.Density = rho;
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exitPort.Temperature = p / (rho * 287.05);
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exitPort.MassFlowRate = -outflowMassFlow;
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exitPort.SpecificEnthalpy = 0.0;
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exhaustPort.Pressure = p;
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exhaustPort.Density = rho;
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exhaustPort.Temperature = p / (rho * 287.05);
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exhaustPort.MassFlowRate = -outflowMassFlow;
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exhaustPort.SpecificEnthalpy = 0.0;
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}
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private void UpdateIntakePort()
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{
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// Use the actual valve mass flow (positive = into cylinder)
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double mdotIntoEngine = couplingIntake.LastMassFlowIntoVolume;
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// Use cylinder pressure/density for the port state (or intake pipe last cell)
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double pCyl = engineCyl.Cylinder.Pressure;
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double rhoCyl = engineCyl.Cylinder.Density;
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intakePort.Pressure = Math.Max(pCyl, 100);
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intakePort.Density = Math.Max(rhoCyl, 1e-6);
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intakePort.Temperature = engineCyl.Cylinder.Temperature;
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intakePort.MassFlowRate = mdotIntoEngine;
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intakePort.SpecificEnthalpy = 0.0;
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}
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// ==================== Drawing ====================
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public override void Draw(RenderWindow target)
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{
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float winW = target.GetView().Size.X;
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@@ -169,10 +227,10 @@ namespace FluidSim.Core
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return (float)Math.Clamp(t, -1.0, 1.0);
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}
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// ---- Cylinder ----
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float cylW = 80f, cylH = 150f;
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var cylRect = new RectangleShape(new Vector2f(cylW, cylH));
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cylRect.Position = new Vector2f(40f, centerY - cylH / 2f);
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cylRect.Position = new Vector2f(200f, centerY - cylH / 2f);
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double tempCyl = engineCyl.Cylinder.Temperature;
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float tnCyl = NormaliseTemperature(tempCyl);
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byte rC = (byte)(tnCyl > 0 ? 255 * tnCyl : 0);
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@@ -181,33 +239,60 @@ namespace FluidSim.Core
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cylRect.FillColor = new Color(rC, gC, bC);
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target.Draw(cylRect);
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int n = exhaustPipe.GetCellCount();
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float pipeStartX = 120f, pipeEndX = winW - 60f;
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float pipeLen = pipeEndX - pipeStartX;
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float dx = pipeLen / (n - 1);
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float baseRadius = 20f;
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// ---- Piston ----
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float pistonWidth = cylW - 12f;
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float pistonHeight = 16f;
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float pistonFraction = (float)engineCyl.PistonPositionFraction;
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float pistonTopY = cylRect.Position.Y + pistonFraction * (cylH - pistonHeight);
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var pistonRect = new RectangleShape(new Vector2f(pistonWidth, pistonHeight))
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{
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Position = new Vector2f(cylRect.Position.X + 6f, pistonTopY),
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FillColor = new Color(80, 80, 80)
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};
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target.Draw(pistonRect);
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// ---- Exhaust pipe (rightwards) ----
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DrawPipe(target, exhaustPipe, startX: 280f, endX: winW - 60f, centerY,
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T_ambient, T_hot, T_cold, R, NormaliseTemperature, true);
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// ---- Intake pipe (leftwards) ----
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DrawPipe(target, intakePipe, startX: 200f, endX: 20f, centerY,
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T_ambient, T_hot, T_cold, R, NormaliseTemperature, false);
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}
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private void DrawPipe(RenderWindow target, Pipe1D pipe,
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float startX, float endX, float centerY,
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float T_ambient, float T_hot, float T_cold, float R,
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Func<double, float> normaliseTemp, bool leftToRight)
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{
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int n = pipe.GetCellCount();
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float dir = leftToRight ? 1f : -1f;
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float pipeLen = Math.Abs(endX - startX);
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float dx = pipeLen / (n - 1) * dir;
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float baseRadius = leftToRight ? 20f : 14f; // exhaust thicker, intake thinner
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var vertices = new Vertex[n * 2];
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float ambPress = 101325f;
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for (int i = 0; i < n; i++)
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{
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float x = pipeStartX + i * dx;
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double p = exhaustPipe.GetCellPressure(i);
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double rho = exhaustPipe.GetCellDensity(i);
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float x = startX + i * dx;
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double p = pipe.GetCellPressure(i);
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double rho = pipe.GetCellDensity(i);
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double T = p / (rho * R);
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float r = baseRadius * 0.3f * (float)(1.0 + (p - ambPress) / ambPress);
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if (r < 2f) r = 2f;
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float tn = NormaliseTemperature(T);
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byte rCol = (byte)(tn > 0 ? 255 * tn : 0);
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byte bCol = (byte)(tn < 0 ? -255 * tn : 0);
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byte gCol = (byte)(255 * (1 - Math.Abs(tn)));
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var col = new Color(rCol, gCol, bCol);
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float tn = normaliseTemp(T);
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byte rC = (byte)(tn > 0 ? 255 * tn : 0);
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byte bC = (byte)(tn < 0 ? -255 * tn : 0);
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byte gC = (byte)(255 * (1 - Math.Abs(tn)));
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var col = new Color(rC, gC, bC);
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vertices[i * 2] = new Vertex(new Vector2f(x, centerY - r), col);
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vertices[i * 2 + 1] = new Vertex(new Vector2f(x, centerY + r), col);
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}
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target.Draw(vertices, PrimitiveType.TriangleStrip);
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}
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}
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