using FluidSim.Components; using FluidSim.Core; using FluidSim.Interfaces; using SFML.Graphics; using SFML.System; using System; namespace FluidSim.Tests { public class SingleCylScenario : Scenario { private Crankshaft crankshaft; private Cylinder cylinder; private PipeSystem pipeSystem; private BoundarySystem boundaries; private Solver solver; private Volume0D intakePlenum; private Port plenumInlet, plenumOutlet; private Volume0D exhaustCollector; private Port colIn, colOut; private int throttleAreaIdx, plenumRunnerAreaIdx, intakeValveIdx, exhaustValveIdx; private float[] orificeAreas; private int intakeOpenIdx, exhaustOpenIdx; private SoundProcessor exhaustSound, intakeSound; private OutdoorExhaustReverb reverb; private double dt; private int stepCount; public float MaxThrottleArea = 100e-4f; // 1 cm² // pipe area for open end calculations private float pipeArea; public override void Initialize(int sampleRate) { dt = 1.0 / sampleRate; // ---- Crankshaft ---- crankshaft = new Crankshaft(600); crankshaft.Inertia = 0.05f; crankshaft.FrictionConstant = 2f; crankshaft.FrictionViscous = 0.01f; // ---- Cylinder ---- float bore = 0.056f, stroke = 0.057f, conRod = 0.110f, compRatio = 9.2f; float ivo = 350f, ivc = 580f, evo = 120f, evc = 370f; cylinder = new Cylinder(bore, stroke, conRod, compRatio, ivo, ivc, evo, evc, crankshaft) { IntakeValveDiameter = 0.03f, IntakeValveLift = 0.005f, ExhaustValveDiameter = 0.028f, ExhaustValveLift = 0.005f }; // ---- Pipe system ---- int totalCells = 10 + 10 + 50; int[] pipeStart = { 0, 10, 20 }; int[] pipeEnd = { 10, 20, 70 }; float[] area = new float[totalCells]; float[] dx = new float[totalCells]; float pipeDiameter = 0.02f; // 2 cm pipeArea = MathF.PI * 0.25f * pipeDiameter * pipeDiameter; float areaVal = pipeArea; float intakeLenBefore = 0.2f, intakeLenRunner = 0.2f, exhaustLen = 0.5f; for (int i = 0; i < totalCells; i++) { area[i] = areaVal; if (i < 10) dx[i] = intakeLenBefore / 10f; else if (i < 20) dx[i] = intakeLenRunner / 10f; else dx[i] = exhaustLen / 50f; } pipeSystem = new PipeSystem(totalCells, pipeStart, pipeEnd, area, dx, 1.225f, 0f, 101325f); pipeSystem.DampingMultiplier = 1.0f; pipeSystem.EnergyRelaxationRate = 0.5f; pipeSystem.AmbientPressure = 101325f; // ---- Volumes ---- intakePlenum = new Volume0D(100e-6f, 101325f, 300f); // 100 mL plenumInlet = intakePlenum.CreatePort(); plenumOutlet = intakePlenum.CreatePort(); exhaustCollector = new Volume0D(10e-6f, 101325f, 800f); // 10 mL (unused but present) colIn = exhaustCollector.CreatePort(); colOut = exhaustCollector.CreatePort(); // ---- Boundary system ---- boundaries = new BoundarySystem(pipeSystem, maxOrifices: 4, maxOpenEnds: 2); throttleAreaIdx = 0; plenumRunnerAreaIdx = 1; intakeValveIdx = 2; exhaustValveIdx = 3; // Intake open end (pipe0 left) boundaries.AddOpenEnd(pipeIndex: 0, isLeftEnd: true, 101325f, pipeArea); intakeOpenIdx = 0; // Throttle orifice (plenum inlet to pipe0 right) boundaries.AddOrifice(plenumInlet, pipeIndex: 0, isLeftEnd: false, throttleAreaIdx, 0.2f); // Plenum to runner (plenum outlet to pipe1 left) boundaries.AddOrifice(plenumOutlet, pipeIndex: 1, isLeftEnd: true, plenumRunnerAreaIdx, 1f); // Intake valve (cylinder intake to pipe1 right) boundaries.AddOrifice(cylinder.IntakePort, pipeIndex: 1, isLeftEnd: false, intakeValveIdx, 1f); // Exhaust valve (cylinder exhaust to pipe2 left) boundaries.AddOrifice(cylinder.ExhaustPort, pipeIndex: 2, isLeftEnd: true, exhaustValveIdx, 1f); // Exhaust open end (pipe2 right) boundaries.AddOpenEnd(pipeIndex: 2, isLeftEnd: false, 101325f, pipeArea); exhaustOpenIdx = 1; orificeAreas = new float[4]; orificeAreas[plenumRunnerAreaIdx] = areaVal; // fixed plenum->runner area // ---- Solver ---- solver = new Solver { SubStepCount = 4, EnableProfiling = false }; solver.SetTimeStep(dt); solver.SetPipeSystem(pipeSystem); solver.SetBoundarySystem(boundaries); solver.AddComponent(cylinder); solver.AddComponent(intakePlenum); solver.AddComponent(exhaustCollector); // ---- Sound ---- exhaustSound = new SoundProcessor(sampleRate, 1f) { Gain = 20f }; intakeSound = new SoundProcessor(sampleRate, 1f) { Gain = 20f }; reverb = new OutdoorExhaustReverb(sampleRate); stepCount = 0; Console.WriteLine("TestScenario ready."); } public override float Process() { crankshaft.Step((float)dt); cylinder.PreStep((float)dt); // Update variable orifice areas float throttledArea = MaxThrottleArea * Math.Clamp(Throttle, 0.0001f, 1f); orificeAreas[throttleAreaIdx] = throttledArea; orificeAreas[intakeValveIdx] = cylinder.IntakeValveArea; orificeAreas[exhaustValveIdx] = cylinder.ExhaustValveArea; boundaries.SetOrificeAreas(orificeAreas); solver.Step(); stepCount++; // Retrieve open‑end mass flows for sound synthesis float exhaustFlow = boundaries.GetOpenEndMassFlow(exhaustOpenIdx); float intakeFlow = boundaries.GetOpenEndMassFlow(intakeOpenIdx); float exhaustDry = exhaustSound.Process(exhaustFlow); float intakeDry = intakeSound.Process(intakeFlow); if (stepCount % 1000 == 0) { float rpm = crankshaft.AngularVelocity * 60f / (2f * MathF.PI); float crankDeg = crankshaft.CrankAngle; // public property on Cylinder Console.WriteLine($"Step {stepCount}, CA={crankDeg:F1} deg, RPM={rpm:F0}, CylP={cylinder.Pressure / 1e5f:F2} bar"); Console.WriteLine($" intake flow: {intakeFlow:F6}, exhaust flow: {exhaustFlow:F6}"); // Pipe 0 (intake before throttle) var (r0L, u0L, p0L) = pipeSystem.GetInteriorStateLeft(0); var (r0R, u0R, p0R) = pipeSystem.GetInteriorStateRight(0); Console.WriteLine($" Pipe0 L: rho={r0L:F4} u={u0L:F3} p={p0L/1e5:F3}bar | R: rho={r0R:F4} u={u0R:F3} p={p0R/1e5:F3}bar"); // Pipe 1 (runner) var (r1L, u1L, p1L) = pipeSystem.GetInteriorStateLeft(1); var (r1R, u1R, p1R) = pipeSystem.GetInteriorStateRight(1); Console.WriteLine($" Pipe1 L: rho={r1L:F4} u={u1L:F3} p={p1L/1e5:F3}bar | R: rho={r1R:F4} u={u1R:F3} p={p1R/1e5:F3}bar"); // Pipe 2 (exhaust) var (r2L, u2L, p2L) = pipeSystem.GetInteriorStateLeft(2); var (r2R, u2R, p2R) = pipeSystem.GetInteriorStateRight(2); Console.WriteLine($" Pipe2 L: rho={r2L:F4} u={u2L:F3} p={p2L/1e5:F3}bar | R: rho={r2R:F4} u={u2R:F3} p={p2R/1e5:F3}bar"); // Plenum and cylinder mass Console.WriteLine($" Plenum P={intakePlenum.Pressure/1e5:F3}bar, mass={intakePlenum.Mass:E4} kg"); Console.WriteLine($" Cyl mass={cylinder.Mass:E4} kg"); } return reverb.Process(intakeDry + exhaustDry); } public override void Draw(RenderWindow target) { float winW = target.GetView().Size.X; float winH = target.GetView().Size.Y; float intakeY = winH / 2f - 40f; float exhaustY = winH / 2f + 80f; float openEndX = 40f; // Intake pipe before throttle (pipe 0) float pipe1StartX = openEndX; float pipe1EndX = pipe1StartX + 120f; DrawPipe(target, pipeSystem, 0, intakeY, pipe1StartX, pipe1EndX); // Throttle symbol float throttleX = pipe1EndX + 5f; var throttleRect = new RectangleShape(new Vector2f(8f, 30f)) { FillColor = Color.Yellow, Position = new Vector2f(throttleX, intakeY - 15f) }; target.Draw(throttleRect); // Plenum float plenW = 60f, plenH = 80f; float plenLeftX = throttleX + 10f; float plenCenterX = plenLeftX + plenW / 2f; float plenTopY = intakeY - plenH / 2f; DrawVolume(target, intakePlenum, plenCenterX, plenTopY, plenW, plenH); // Runner pipe (pipe 1) float runnerStartX = plenLeftX + plenW + 5f; float runnerEndX = runnerStartX + 100f; DrawPipe(target, pipeSystem, 1, intakeY, runnerStartX, runnerEndX); // Cylinder float cylCX = runnerEndX + 50f; float cylTopY = intakeY - 120f; float cylW = 80f, cylMaxH = 240f; DrawCylinder(target, cylinder, cylCX, cylTopY, cylW, cylMaxH); // Exhaust pipe (pipe 2) float exhStartX = cylCX + cylW / 2f + 20f; float exhEndX = winW - 60f; DrawPipe(target, pipeSystem, 2, exhaustY, exhStartX, exhEndX); } } }