grillkol/FluidSim
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

added two stroke scenario with vehicle

Browse Source
This commit is contained in:
max
2026-06-09 21:35:48 +02:00
parent ac2eab6f83
commit 1240ebc33d
8 changed files with 901 additions and 232 deletions
Download Patch File Download Diff File Expand all files Collapse all files

31
Scenarios/Scenario.cs
View File

@@ -13,12 +13,16 @@ namespace FluidSim.Tests
protected const float AmbientTemperature = 300f;
public float Throttle { get; set; }
public float Load { get; set; }
public float Clutch { get; set; } // 0 = engaged, 1 = fully disengaged (manual lever)
public Font? Font { get; set; }
public abstract void Initialize(int sampleRate);
public abstract float Process();
public abstract void Draw(RenderWindow target);
public virtual void ShiftUp() { }
public virtual void ShiftDown() { }
// ---- Dyno curve graph ----
private const float RpmBinSize = 50f;
private readonly List<(float powerKw, float torqueNm)> _dynoBins = new();
@@ -259,7 +263,7 @@ namespace FluidSim.Tests
target.Draw(border);
}
protected void DrawCylinder(RenderWindow target, Cylinder cylinder,
protected void DrawCylinder(RenderWindow target, EngineCylinder cylinder,
float centerX, float topY, float width, float maxHeight)
{
float fraction = cylinder.PistonFraction;
@@ -298,7 +302,8 @@ namespace FluidSim.Tests
}
protected void DrawPipe(RenderWindow target, PipeSystem pipeSystem, int pipeIndex,
float pipeCenterY, float pipeStartX, float pipeEndX)
float pipeCenterY, float pipeStartX, float pipeEndX,
float areaScale = 0f)
{
int start = pipeSystem.GetPipeStart(pipeIndex);
int end = pipeSystem.GetPipeEnd(pipeIndex);
@@ -307,20 +312,34 @@ namespace FluidSim.Tests
float pipeLen = pipeEndX - pipeStartX;
float dx = pipeLen / (n - 1);
float baseRadius = 25f;
var centers = new float[n];
var radii = new float[n];
var temps = new float[n];
for (int i = 0; i < n; i++)
{
int cell = start + i;
float p = pipeSystem.GetCellPressure(cell);
float rho = pipeSystem.GetCellDensity(cell);
temps[i] = p / MathF.Max(rho * 287f, 1e-12f);
float dev = MathF.Tanh((p - AmbientPressure) / AmbientPressure * 0.5f);
radii[i] = baseRadius * (1f + dev * 2f);
if (radii[i] < 2f) radii[i] = 2f;
if (areaScale > 0f)
{
// Use actual cell area to determine visual radius
float area = pipeSystem.GetCellArea(cell);
radii[i] = MathF.Sqrt(area / MathF.PI) * areaScale;
if (radii[i] < 1f) radii[i] = 1f;
}
else
{
// Original pressure‑based radius
float dev = MathF.Tanh((p - AmbientPressure) / AmbientPressure * 0.5f);
float baseRadius = 25f; // default visual radius for constant‑area pipes
radii[i] = baseRadius * (1f + dev * 2f);
if (radii[i] < 2f) radii[i] = 2f;
}
centers[i] = pipeStartX + i * dx;
}

293
Scenarios/TwoStrokeScenario.cs Normal file
View File

@@ -0,0 +1,293 @@
using FluidSim.Components;
using FluidSim.Core;
using FluidSim.Interfaces;
using FluidSim.Utils;
using SFML.Graphics;
using SFML.System;
using System;
namespace FluidSim.Tests
{
public class TwoStrokeScenario : Scenario
{
private Crankshaft crankshaft;
private TwoStrokeCylinder cylinder;
private PipeSystem pipeSystem;
private BoundarySystem boundaries;
private Solver solver;
private Volume0D intakePlenum;
private Port plenumInlet, plenumOutlet;
private Volume0D exhaustMuffler;
private Port mufflerIn, mufflerOut;
private Vehicle vehicle;
private int throttleAreaIdx, plenumRunnerIdx, intakeValveIdx, exhaustValveIdx;
private float[] orificeAreas;
private int intakeOpenIdx, exhaustOpenIdx;
private SoundProcessor exhaustSound, intakeSound;
private OutdoorExhaustReverb reverb;
private double dt;
private int stepCount;
private float _maxThrottleArea;
private float intakePipeArea, exhaustHeaderArea;
// -- Override shift from Scenario base class --
public override void ShiftUp() => vehicle.ShiftUp();
public override void ShiftDown() => vehicle.ShiftDown();
public override void Initialize(int sampleRate)
{
dt = 1.0 / sampleRate;
// ---- Vehicle ----
vehicle = new Vehicle();
// ---- Throttle (38 mm) ----
_maxThrottleArea = (float)Units.AreaFromDiameter(38 * Units.mm);
// ---- Crankshaft ----
crankshaft = new Crankshaft(2000);
crankshaft.CycleLength = 2f * MathF.PI; // two‑stroke
crankshaft.Inertia = 0.05f; // engine's own inertia (light)
crankshaft.FrictionConstant = 2.5f;
crankshaft.FrictionViscous = 0.0015f;
// ---- Cylinder (125cc) ----
float bore = 0.054f, stroke = 0.0545f, conRod = 0.109f, compRatio = 12.5f;
// Symmetric durations (around BDC)
float transferDuration = 130f; // 130°
float exhaustDuration = 190f; // 190°
cylinder = new TwoStrokeCylinder(bore, stroke, conRod, compRatio,
transferDuration, exhaustDuration,
crankshaft)
{
IntakeValveDiameter = 0.038f,
IntakeValveLift = 0.010f,
ExhaustValveDiameter = 0.040f,
ExhaustValveLift = 0.010f
};
// ---- Pipe system (60 exhaust cells, simple diffuser) ----
int intakeCells = 8;
int runnerCells = 8;
int exhaustCells = 60;
int totalCells = intakeCells + runnerCells + exhaustCells;
int[] pipeStart = { 0, intakeCells, intakeCells + runnerCells };
int[] pipeEnd = { intakeCells, intakeCells + runnerCells, totalCells };
float[] area = new float[totalCells];
float[] dx = new float[totalCells];
float intakeDia = 0.038f;
float intakeLenBefore = 0.15f;
float intakeLenRunner = 0.20f;
intakePipeArea = MathF.PI * 0.25f * intakeDia * intakeDia;
// Single‑stage diffuser – 840 mm total, easy to tune
float headerDia = 0.042f, headerLen = 0.160f;
float diffuserLen = 0.250f, diffuserEndDia = 0.070f; // belly
float bellyLen = 0.240f;
float convergentLen = 0.120f;
float stingerDia = 0.026f, stingerLen = 0.070f;
// total = 0.16 + 0.25 + 0.24 + 0.12 + 0.07 = 0.84 m
exhaustHeaderArea = MathF.PI * 0.25f * headerDia * headerDia;
float bellyArea = MathF.PI * 0.25f * diffuserEndDia * diffuserEndDia;
float stingerArea = MathF.PI * 0.25f * stingerDia * stingerDia;
float totalExhaustLen = headerLen + diffuserLen + bellyLen + convergentLen + stingerLen; // 840 mm
int headerCells = (int)(exhaustCells * (headerLen / totalExhaustLen));
int diffuserCells = (int)(exhaustCells * (diffuserLen / totalExhaustLen));
int bellyCells = (int)(exhaustCells * (bellyLen / totalExhaustLen));
int convergentCells = (int)(exhaustCells * (convergentLen / totalExhaustLen));
int stingerCells = exhaustCells - headerCells - diffuserCells - bellyCells - convergentCells;
// Fill cells
for (int i = 0; i < intakeCells; i++)
{ area[i] = intakePipeArea; dx[i] = intakeLenBefore / intakeCells; }
for (int i = intakeCells; i < intakeCells + runnerCells; i++)
{ area[i] = intakePipeArea; dx[i] = intakeLenRunner / runnerCells; }
int exhStart = intakeCells + runnerCells;
int idx = 0;
for (int i = exhStart; i < totalCells; i++)
{
if (idx < headerCells)
{ area[i] = exhaustHeaderArea; dx[i] = headerLen / headerCells; }
else if (idx < headerCells + diffuserCells)
{
float t = (idx - headerCells) / (float)(diffuserCells - 1);
float dia = headerDia + (diffuserEndDia - headerDia) * t;
area[i] = MathF.PI * 0.25f * dia * dia;
dx[i] = diffuserLen / diffuserCells;
}
else if (idx < headerCells + diffuserCells + bellyCells)
{ area[i] = bellyArea; dx[i] = bellyLen / bellyCells; }
else if (idx < headerCells + diffuserCells + bellyCells + convergentCells)
{
float t = (idx - headerCells - diffuserCells - bellyCells) / (float)(convergentCells - 1);
float dia = diffuserEndDia + (stingerDia - diffuserEndDia) * t;
area[i] = MathF.PI * 0.25f * dia * dia;
dx[i] = convergentLen / convergentCells;
}
else
{ area[i] = stingerArea; dx[i] = stingerLen / stingerCells; }
idx++;
}
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(0.5e-3f, 101325f, 300f);
plenumInlet = intakePlenum.CreatePort();
plenumOutlet = intakePlenum.CreatePort();
exhaustMuffler = new Volume0D(5e-4f, 101325f, 600f);
mufflerIn = exhaustMuffler.CreatePort();
mufflerOut = exhaustMuffler.CreatePort();
// ---- Boundary system ----
boundaries = new BoundarySystem(pipeSystem, maxOrifices: 4, maxOpenEnds: 2);
throttleAreaIdx = 0; plenumRunnerIdx = 1; intakeValveIdx = 2; exhaustValveIdx = 3;
boundaries.AddOpenEnd(pipeIndex: 0, isLeftEnd: true, 101325f, intakePipeArea);
intakeOpenIdx = 0;
boundaries.AddOpenEnd(pipeIndex: 2, isLeftEnd: false, 101325f, stingerArea);
exhaustOpenIdx = 1;
boundaries.AddOrifice(plenumInlet, 0, false, throttleAreaIdx, 0.7f);
boundaries.AddOrifice(plenumOutlet, 1, true, plenumRunnerIdx, 1.0f);
boundaries.AddOrifice(cylinder.IntakePort, 1, false, intakeValveIdx, 0.65f);
boundaries.AddOrifice(cylinder.ExhaustPort,2, true, exhaustValveIdx, 0.68f);
orificeAreas = new float[4];
orificeAreas[plenumRunnerIdx] = intakePipeArea;
// ---- Solver ----
solver = new Solver { SubStepCount = 4, EnableProfiling = false }; // 4 sub‑steps for 60 cells
solver.SetTimeStep(dt);
solver.SetPipeSystem(pipeSystem);
solver.SetBoundarySystem(boundaries);
solver.AddComponent(cylinder);
solver.AddComponent(intakePlenum);
solver.AddComponent(exhaustMuffler);
// ---- Sound ----
exhaustSound = new SoundProcessor(sampleRate, 1f) { Gain = 10f };
intakeSound = new SoundProcessor(sampleRate, 1f) { Gain = 10f };
reverb = new OutdoorExhaustReverb(sampleRate);
stepCount = 0;
Console.WriteLine("125cc Two‑Stroke with vehicle coupling ready.");
}
public override float Process()
{
float engineRpm = crankshaft.AngularVelocity * 60f / (2f * MathF.PI);
vehicle.ClutchInput = Clutch;
var (clutchTorque, effectiveInertia) = vehicle.Update(engineRpm, crankshaft.Inertia, (float)dt);
crankshaft.SetEffectiveInertia(effectiveInertia);
crankshaft.SetLoadTorque(clutchTorque); // clutch torque now includes drag when locked
crankshaft.Step((float)dt);
cylinder.PreStep((float)dt);
float throttledArea = _maxThrottleArea * Math.Clamp(Throttle, 0.001f, 1f);
orificeAreas[throttleAreaIdx] = throttledArea;
orificeAreas[intakeValveIdx] = cylinder.IntakeValveArea;
orificeAreas[exhaustValveIdx] = cylinder.ExhaustValveArea;
boundaries.SetOrificeAreas(orificeAreas);
solver.Step();
stepCount++;
float exhaustFlow = boundaries.GetOpenEndMassFlow(exhaustOpenIdx);
float intakeFlow = boundaries.GetOpenEndMassFlow(intakeOpenIdx);
float exhaustDry = exhaustSound.Process(exhaustFlow);
float intakeDry = intakeSound.Process(intakeFlow);
if (stepCount % 2000 == 0)
{
float rpm = crankshaft.AngularVelocity * 60f / (2f * MathF.PI);
Console.WriteLine($"Step {stepCount}, RPM={rpm:F0}, Gear={vehicle.CurrentGear}, Speed={vehicle.SpeedKmh:F0} km/h");
}
return reverb.Process((intakeDry + exhaustDry) * 0.5f);
}
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
float x = openEndX;
float w = 120f;
DrawPipe(target, pipeSystem, 0, intakeY, x, x + w);
// Throttle
float throttleX = x + w + 5f;
var throttleRect = new RectangleShape(new Vector2f(8f, 30f))
{
FillColor = Color.Yellow,
Position = new Vector2f(throttleX, intakeY - 15f)
};
target.Draw(throttleRect);
// Plenum
float plenW = 40f, plenH = 60f;
float plenX = throttleX + 10f;
DrawVolume(target, intakePlenum, plenX + plenW / 2f, intakeY - plenH / 2f, plenW, plenH);
// Runner
float runnerStartX = plenX + plenW + 5f;
DrawPipe(target, pipeSystem, 1, intakeY, runnerStartX, runnerStartX + 100f);
// Cylinder
float cylCX = runnerStartX + 150f;
float cylTopY = intakeY - 120f;
DrawCylinder(target, cylinder, cylCX, cylTopY, 80f, 240f);
// Exhaust pipe
float exhStartX = cylCX + 40f + 20f;
DrawPipe(target, pipeSystem, 2, exhaustY, exhStartX, winW - 60f, areaScale: 1000f);
// Labels
float rpm = crankshaft.AngularVelocity * 60f / (2f * MathF.PI);
float powerKw = crankshaft.AveragePower * 1e-3f;
DrawLabel(target, $"RPM: {rpm:F0}", new Vector2f(20, 90), Color.White, 24);
DrawLabel(target, $"Power: {powerKw:F2} kW", new Vector2f(20, 115), Color.White, 24);
DrawLabel(target, $"Gear: {vehicle.CurrentGear}", new Vector2f(20, 140), Color.Cyan, 20);
DrawLabel(target, $"Speed: {vehicle.SpeedKmh:F0} km/h", new Vector2f(20, 160), Color.Cyan, 20);
// Dyno curve
float torqueNm = crankshaft.AverageTorque;
UpdateDynoCurve(rpm, powerKw, torqueNm);
DrawDynoCurve(target, winW - 410f, winH - 260f, 400f, 250f, rpm, powerKw);
string gearText = vehicle.CurrentGear == 0 ? "N" : vehicle.CurrentGear.ToString();
DrawLabel(target, $"Gear: {gearText}", new Vector2f(20, 140), Color.Cyan, 20);
DrawLabel(target, $"Speed: {vehicle.SpeedKmh:F0} km/h", new Vector2f(20, 160), Color.Cyan, 20);
DrawLabel(target, vehicle.Engagement > 0.99f ? "Clutch Locked" : "Clutch Slipping", new Vector2f(20, 180), Color.Cyan, 14);
}
}
}