diff --git a/Audio/RingBuffer.cs b/Audio/RingBuffer.cs
new file mode 100644
index 0000000..efdf28c
--- /dev/null
+++ b/Audio/RingBuffer.cs
@@ -0,0 +1,41 @@
+namespace FluidSim.Audio
+{
+ internal class RingBuffer
+ {
+ private readonly float[] buffer;
+ private volatile int readPos;
+ private volatile int writePos;
+
+ public RingBuffer(int capacity)
+ {
+ if ((capacity & (capacity - 1)) != 0)
+ throw new ArgumentException("Capacity must be a power of two.");
+ buffer = new float[capacity];
+ }
+
+ public int Count => (writePos - readPos) & (buffer.Length - 1);
+ public int Space => (readPos - writePos - 1) & (buffer.Length - 1);
+
+ public int Write(float[] data, int count)
+ {
+ int space = Space;
+ int toWrite = Math.Min(count, space);
+ int mask = buffer.Length - 1;
+ for (int i = 0; i < toWrite; i++)
+ buffer[(writePos + i) & mask] = data[i];
+ writePos = (writePos + toWrite) & mask;
+ return toWrite;
+ }
+
+ public int Read(float[] destination, int count)
+ {
+ int available = Count;
+ int toRead = Math.Min(count, available);
+ int mask = buffer.Length - 1;
+ for (int i = 0; i < toRead; i++)
+ destination[i] = buffer[(readPos + i) & mask];
+ readPos = (readPos + toRead) & mask;
+ return toRead;
+ }
+ }
+}
diff --git a/Audio/RingBufferStream.cs b/Audio/RingBufferStream.cs
new file mode 100644
index 0000000..58d3bab
--- /dev/null
+++ b/Audio/RingBufferStream.cs
@@ -0,0 +1,43 @@
+using SFML.Audio;
+using SFML.System;
+
+namespace FluidSim.Audio
+{
+ internal class RingBufferStream : SoundStream
+ {
+ private readonly RingBuffer ringBuffer;
+
+ public RingBufferStream(RingBuffer buffer)
+ {
+ ringBuffer = buffer;
+ // 2 channels, 44.1 kHz, standard stereo mapping
+ Initialize(2, 44100, new[] { SoundChannel.FrontLeft, SoundChannel.FrontRight });
+ }
+
+ protected override bool OnGetData(out short[] samples)
+ {
+ const int monoBlockSize = 512; // number of mono samples we'll read
+ float[] temp = new float[monoBlockSize];
+ int read = ringBuffer.Read(temp, monoBlockSize);
+ samples = new short[monoBlockSize * 2];
+
+ if (read > 0)
+ {
+ for (int i = 0; i < read; i++)
+ {
+ float clamped = Math.Clamp(temp[i], -1f, 1f);
+ short final = (short)(clamped * short.MaxValue);
+ samples[i * 2] = final; // left
+ samples[i * 2 + 1] = final; // right
+ }
+ }
+ for (int i = read * 2; i < samples.Length; i++)
+ samples[i] = 0;
+
+ return true;
+ }
+
+ protected override void OnSeek(Time timeOffset) =>
+ throw new NotSupportedException();
+ }
+}
diff --git a/Audio/SoundEngine.cs b/Audio/SoundEngine.cs
new file mode 100644
index 0000000..c8cfb9d
--- /dev/null
+++ b/Audio/SoundEngine.cs
@@ -0,0 +1,45 @@
+namespace FluidSim.Audio;
+
+public class SoundEngine : IDisposable
+{
+ private readonly RingBuffer ringBuffer;
+ private readonly RingBufferStream stream;
+ private bool isPlaying;
+
+ public SoundEngine(int bufferCapacity = 16384)
+ {
+ ringBuffer = new RingBuffer(bufferCapacity);
+ stream = new RingBufferStream(ringBuffer);
+ }
+
+ public void Start()
+ {
+ if (isPlaying) return;
+ stream.Play();
+ isPlaying = true;
+ }
+
+ public void Stop()
+ {
+ if (!isPlaying) return;
+ stream.Stop();
+ isPlaying = false;
+ float[] drain = new float[ringBuffer.Count];
+ ringBuffer.Read(drain, drain.Length);
+ }
+
+ public int WriteSamples(float[] data, int count) =>
+ ringBuffer.Write(data, count);
+
+ public float Volume
+ {
+ get => stream.Volume;
+ set => stream.Volume = value;
+ }
+
+ public void Dispose()
+ {
+ Stop();
+ stream.Dispose();
+ }
+}
\ No newline at end of file
diff --git a/Audio/SoundProcessor.cs b/Audio/SoundProcessor.cs
new file mode 100644
index 0000000..18b64d6
--- /dev/null
+++ b/Audio/SoundProcessor.cs
@@ -0,0 +1,29 @@
+using FluidSim.Components;
+using FluidSim.Interfaces;
+using System;
+
+namespace FluidSim.Audio
+{
+ public static class SoundProcessor
+ {
+ public static float MaxDeltaP { get; set; } = 100_000f;
+ public static float MaxArea { get; set; } = 1e-4f;
+ public static float MaxVelocity { get; set; } = 343f;
+ public static float ReferenceDensity { get; set; } = 1.225f;
+ public static float ReferenceSpeedOfSound { get; set; } = 343f;
+ public static float Gain { get; set; } = 1.0f;
+
+ public static double ComputeSample(Connection conn)
+ {
+ Port portA = conn.PortA;
+ Port portB = conn.PortB;
+
+ double pressureUp = portA.Pressure;
+ double pressureDown = portB.Pressure;
+
+ // No flow or no pressure drop → silence
+ double deltaP = pressureUp - pressureDown;
+ return deltaP / 1;
+ }
+ }
+}
\ No newline at end of file
diff --git a/Components/Pipe1D.cs b/Components/Pipe1D.cs
index 5b6e2aa..2ff7e6d 100644
--- a/Components/Pipe1D.cs
+++ b/Components/Pipe1D.cs
@@ -12,29 +12,52 @@ namespace FluidSim.Components
private int _n;
private double _dx, _dt, _gamma = 1.4, _area;
private double[] _rho, _rhou, _E;
+ private double _hydraulicDiameter;
- // Volume states at boundaries
private double _rhoLeft, _pLeft, _rhoRight, _pRight;
private bool _leftBCSet, _rightBCSet;
- public double FrictionFactor { get; set; } = 0.02;
+ public double FrictionFactor { get; set; }
public int GetCellCount() => _n;
public double GetCellDensity(int i) => _rho[i];
public double GetCellPressure(int i) => Pressure(i);
public double GetCellVelocity(int i) => _rhou[i] / Math.Max(_rho[i], 1e-12);
- public Pipe1D(double length, double area, int nCells, int sampleRate)
+ ///
+ /// Create a pipe with CFL‑stable automatic cell count.
+ ///
+ /// Pipe length [m].
+ /// Cross‑sectional area [m²].
+ /// Simulation step rate [Hz].
+ /// Speed of sound [m/s] (default 343).
+ /// Darcy friction factor (0 = inviscid).
+ /// CFL safety factor ≤ 1 (0.8 recommended).
+ public Pipe1D(double length, double area, int sampleRate,
+ double c0 = 343.0, double frictionFactor = 0.02,
+ double cflSafety = 0.8)
{
- _n = nCells;
- _dx = length / nCells;
- _dt = 1.0 / sampleRate;
+ if (area <= 0) throw new ArgumentException("Pipe area must be > 0");
_area = area;
+ _dt = 1.0 / sampleRate;
+ FrictionFactor = frictionFactor;
+
+ // Nyquist‑based cell count (wave resolution)
+ double nNyquist = Math.Ceiling(length * sampleRate / c0);
+ // CFL‑stable cell count: dx ≥ maxSpeed·dt / cflSafety, maxSpeed = 2·c0 (supersonic safe)
+ double maxSpeed = 2.0 * c0;
+ double dxMinStable = maxSpeed * _dt / cflSafety;
+ double nStable = Math.Floor(length / dxMinStable);
+
+ _n = Math.Max(2, (int)Math.Min(nNyquist, nStable));
+ _dx = length / _n;
_rho = new double[_n];
_rhou = new double[_n];
_E = new double[_n];
+ _hydraulicDiameter = Math.Max(2.0 * Math.Sqrt(_area / Math.PI), 1e-9);
+
PortA = new Port();
PortB = new Port();
}
@@ -56,7 +79,6 @@ namespace FluidSim.Components
public double GetLeftDensity() => _rho[0];
public double GetRightDensity() => _rho[_n - 1];
- // ★ New: pass both density and pressure from the volume
public void SetLeftVolumeState(double rhoVol, double pVol)
{
_rhoLeft = rhoVol;
@@ -88,22 +110,13 @@ namespace FluidSim.Components
// --- Left boundary (face 0) ---
if (_leftBCSet)
{
- // Ghost = actual volume state (ρ_vol, u=0, p_vol)
- double rhoL = _rhoLeft;
- double uL = 0.0;
- double pL = _pLeft;
-
- double rhoR = _rho[0];
- double uR = _rhou[0] / Math.Max(rhoR, 1e-12);
- double pR = Pressure(0);
-
+ double rhoL = _rhoLeft, uL = 0.0, pL = _pLeft;
+ double rhoR = _rho[0], uR = _rhou[0] / Math.Max(rhoR, 1e-12), pR = Pressure(0);
HLLCFlux(rhoL, uL, pL, rhoR, uR, pR, out Fm[0], out Fp[0], out Fe[0]);
}
else
{
- Fm[0] = 0;
- Fp[0] = Pressure(0);
- Fe[0] = 0;
+ Fm[0] = 0; Fp[0] = Pressure(0); Fe[0] = 0;
}
// --- Internal faces ---
@@ -118,25 +131,16 @@ namespace FluidSim.Components
// --- Right boundary (face n) ---
if (_rightBCSet)
{
- double rhoL = _rho[n - 1];
- double uL = _rhou[n - 1] / Math.Max(rhoL, 1e-12);
- double pL = Pressure(n - 1);
-
- // Ghost = actual volume state (ρ_vol, u=0, p_vol)
- double rhoR = _rhoRight;
- double uR = 0.0;
- double pR = _pRight;
-
+ double rhoL = _rho[n - 1], uL = _rhou[n - 1] / Math.Max(rhoL, 1e-12), pL = Pressure(n - 1);
+ double rhoR = _rhoRight, uR = 0.0, pR = _pRight;
HLLCFlux(rhoL, uL, pL, rhoR, uR, pR, out Fm[n], out Fp[n], out Fe[n]);
}
else
{
- Fm[n] = 0;
- Fp[n] = Pressure(n - 1);
- Fe[n] = 0;
+ Fm[n] = 0; Fp[n] = Pressure(n - 1); Fe[n] = 0;
}
- // --- Cell update ---
+ // --- Cell update (inviscid fluxes) ---
for (int i = 0; i < n; i++)
{
double dM = (Fm[i + 1] - Fm[i]) / _dx;
@@ -149,12 +153,41 @@ namespace FluidSim.Components
if (_rho[i] < 1e-12) _rho[i] = 1e-12;
double kinetic = 0.5 * _rhou[i] * _rhou[i] / _rho[i];
if (_E[i] < kinetic) _E[i] = kinetic;
+
+ // Emergency reset if NaN
+ if (double.IsNaN(_rho[i]) || double.IsNaN(_rhou[i]) || double.IsNaN(_E[i]))
+ {
+ _rho[i] = 1.225; // reset to atmospheric air at 300 K
+ _rhou[i] = 0.0;
+ _E[i] = 101325.0 / (_gamma - 1.0); // internal energy at 1 atm
+ }
}
- // --- Friction disabled ---
- // if (FrictionFactor > 0) { … }
+ // --- Friction (Darcy–Weisbach, energy‑conserving) ---
+ if (FrictionFactor > 0)
+ {
+ double D = _hydraulicDiameter;
+ double twoD = 2.0 * D;
+ for (int i = 0; i < n; i++)
+ {
+ double rho = _rho[i];
+ double u = _rhou[i] / rho;
+ double absU = Math.Abs(u);
+ double src = FrictionFactor * rho * absU * u / twoD;
+ double kinOld = 0.5 * rho * u * u;
+ _rhou[i] -= _dt * src;
+ double uNew = _rhou[i] / rho;
+ double kinNew = 0.5 * rho * uNew * uNew;
+ _E[i] += (kinOld - kinNew);
+ }
+ }
+
+ // --- Publish to ports ---
+ PortA.Pressure = Pressure(0);
+ PortA.Density = _rho[0];
+ PortB.Pressure = Pressure(_n - 1);
+ PortB.Density = _rho[_n - 1];
- // --- Port flows ---
PortA.MassFlowRate = _leftBCSet ? Fm[0] * _area : 0.0;
PortB.MassFlowRate = _rightBCSet ? -Fm[n] * _area : 0.0;
@@ -170,14 +203,24 @@ namespace FluidSim.Components
void HLLCFlux(double rL, double uL, double pL, double rR, double uR, double pR,
out double fm, out double fp, out double fe)
{
- double cL = Math.Sqrt(_gamma * pL / Math.Max(rL, 1e-12));
- double cR = Math.Sqrt(_gamma * pR / Math.Max(rR, 1e-12));
+ const double eps = 1e-12;
+ pL = Math.Max(pL, eps);
+ pR = Math.Max(pR, eps);
+
+ double cL = Math.Sqrt(_gamma * pL / Math.Max(rL, eps));
+ double cR = Math.Sqrt(_gamma * pR / Math.Max(rR, eps));
double EL = pL / ((_gamma - 1) * rL) + 0.5 * uL * uL;
double ER = pR / ((_gamma - 1) * rR) + 0.5 * uR * uR;
+
double SL = Math.Min(uL - cL, uR - cR);
double SR = Math.Max(uL + cL, uR + cR);
- double Ss = (pR - pL + rL * uL * (SL - uL) - rR * uR * (SR - uR))
- / (rL * (SL - uL) - rR * (SR - uR));
+
+ double denom = rL * (SL - uL) - rR * (SR - uR);
+ double Ss;
+ if (Math.Abs(denom) < eps)
+ Ss = 0.5 * (uL + uR);
+ else
+ Ss = (pR - pL + rL * uL * (SL - uL) - rR * uR * (SR - uR)) / denom;
double FrL_m = rL * uL, FrL_p = rL * uL * uL + pL, FrL_e = (rL * EL + pL) * uL;
double FrR_m = rR * uR, FrR_p = rR * uR * uR + pR, FrR_e = (rR * ER + pR) * uR;
@@ -186,16 +229,20 @@ namespace FluidSim.Components
else if (SR <= 0) { fm = FrR_m; fp = FrR_p; fe = FrR_e; }
else if (Ss >= 0)
{
- double rsL = rL * (SL - uL) / (SL - Ss);
- double ps = pL + rL * (SL - uL) * (Ss - uL);
- double EsL = EL + (Ss - uL) * (Ss + pL / (rL * (SL - uL)));
+ double diffSL = SL - uL;
+ if (Math.Abs(diffSL) < eps) diffSL = eps;
+ double rsL = rL * diffSL / (SL - Ss);
+ double ps = pL + rL * diffSL * (Ss - uL);
+ double EsL = EL + (Ss - uL) * (Ss + pL / (rL * diffSL));
fm = rsL * Ss; fp = rsL * Ss * Ss + ps; fe = (rsL * EsL + ps) * Ss;
}
else
{
- double rsR = rR * (SR - uR) / (SR - Ss);
+ double diffSR = SR - uR;
+ if (Math.Abs(diffSR) < eps) diffSR = eps;
+ double rsR = rR * diffSR / (SR - Ss);
double ps = pL + rL * (SL - uL) * (Ss - uL);
- double EsR = ER + (Ss - uR) * (Ss + pR / (rR * (SR - uR)));
+ double EsR = ER + (Ss - uR) * (Ss + pR / (rR * diffSR));
fm = rsR * Ss; fp = rsR * Ss * Ss + ps; fe = (rsR * EsR + ps) * Ss;
}
}
diff --git a/Components/SoundConnection.cs b/Components/SoundConnection.cs
new file mode 100644
index 0000000..3ebe259
--- /dev/null
+++ b/Components/SoundConnection.cs
@@ -0,0 +1,9 @@
+using FluidSim.Interfaces;
+
+namespace FluidSim.Components
+{
+ public class SoundConnection : Connection
+ {
+ public SoundConnection(Port a, Port b) : base(a, b) { }
+ }
+}
\ No newline at end of file
diff --git a/Components/Volume0D.cs b/Components/Volume0D.cs
index b5949a2..d380288 100644
--- a/Components/Volume0D.cs
+++ b/Components/Volume0D.cs
@@ -1,6 +1,4 @@
-using System;
-using FluidSim.Interfaces;
-using FluidSim.Utils;
+using FluidSim.Interfaces;
namespace FluidSim.Components
{
diff --git a/Core/OrificeBoundary.cs b/Core/OrificeBoundary.cs
index 733eba2..87c1e85 100644
--- a/Core/OrificeBoundary.cs
+++ b/Core/OrificeBoundary.cs
@@ -1,5 +1,4 @@
-using System;
-using FluidSim.Components;
+using FluidSim.Components;
namespace FluidSim.Core
{
diff --git a/Core/Simulation.cs b/Core/Simulation.cs
deleted file mode 100644
index 2b310c5..0000000
--- a/Core/Simulation.cs
+++ /dev/null
@@ -1,67 +0,0 @@
-using System;
-using FluidSim.Components;
-using FluidSim.Utils;
-
-namespace FluidSim.Core
-{
- public static class Simulation
- {
- private static Solver solver;
- private static Volume0D volA, volB;
- private static Pipe1D pipe;
- private static Connection connA, connB;
- private static int stepCount;
- private static double time;
- private static double dt;
-
- public static void Initialize(int sampleRate)
- {
- dt = 1.0 / sampleRate;
-
- double V = 5.0 * Units.L;
- volA = new Volume0D(V, 1.1 * Units.atm, Units.Celsius(20), sampleRate);
- volB = new Volume0D(V, 1.0 * Units.atm, Units.Celsius(20), sampleRate);
-
- double length = 150 * Units.mm;
- double diameter = 25 * Units.mm;
- double area = Units.AreaFromDiameter(25, Units.mm);
- int nCells = 10;
-
- pipe = new Pipe1D(length, area, nCells, sampleRate);
- pipe.SetUniformState(volA.Density, 0.0, volA.Pressure);
- pipe.FrictionFactor = 0.02;
-
- // Connections with orifice area equal to pipe area (flange joint)
- connA = new Connection(volA.Port, pipe.PortA) { Area = area, DischargeCoefficient = 1.0, Gamma = 1.4 };
- connB = new Connection(pipe.PortB, volB.Port) { Area = area, DischargeCoefficient = 1.0, Gamma = 1.4 };
-
- solver = new Solver();
- solver.AddVolume(volA);
- solver.AddVolume(volB);
- solver.AddPipe(pipe);
- solver.AddConnection(connA);
- solver.AddConnection(connB);
- }
-
- public static float Process()
- {
- solver.Step();
- time += dt;
- stepCount++;
- Log();
- return 0f;
- }
-
- public static void Log()
- {
- if (stepCount <= 50 || stepCount % 200 == 0)
- {
- Console.WriteLine(
- $"t = {time * 1e3:F3} ms Step {stepCount:D4}: " +
- $"PA = {volA.Pressure / 1e5:F6} bar, " +
- $"PB = {volB.Pressure / 1e5:F6} bar, " +
- $"FlowA = {pipe.PortA.MassFlowRate * 1e3:F2} g/s");
- }
- }
- }
-}
\ No newline at end of file
diff --git a/Core/Solver.cs b/Core/Solver.cs
index 0c7807f..6e74ab9 100644
--- a/Core/Solver.cs
+++ b/Core/Solver.cs
@@ -1,4 +1,4 @@
-using System.Collections.Generic;
+using FluidSim.Audio;
using FluidSim.Components;
using FluidSim.Interfaces;
@@ -10,17 +10,51 @@ namespace FluidSim.Core
private readonly List _pipes = new();
private readonly List _connections = new();
+ public float LastSample { get; private set; }
+
public void AddVolume(Volume0D v) => _volumes.Add(v);
public void AddPipe(Pipe1D p) => _pipes.Add(p);
public void AddConnection(Connection c) => _connections.Add(c);
public void Step()
{
- // 1. Volumes publish state to their ports
+ // 1. Publish volume states to their own ports
foreach (var v in _volumes)
v.PushStateToPort();
- // 2. Set volume states as boundary conditions on pipes
+ // 2. Handle direct volume‑to‑volume connections
+ foreach (var conn in _connections)
+ {
+ if (IsVolumePort(conn.PortA) && IsVolumePort(conn.PortB))
+ {
+ Volume0D volA = _volumes.Find(v => v.Port == conn.PortA);
+ Volume0D volB = _volumes.Find(v => v.Port == conn.PortB);
+
+ if (volA == null || volB == null) continue;
+
+ double pA = volA.Pressure, rhoA = volA.Density;
+ double pB = volB.Pressure, rhoB = volB.Density;
+
+ double mdot = OrificeBoundary.MassFlow(pA, rhoA, pB, rhoB, conn);
+
+ if (mdot > 0) // A → B
+ {
+ volA.Port.MassFlowRate = -mdot;
+ volB.Port.MassFlowRate = mdot;
+ volB.Port.SpecificEnthalpy = volA.SpecificEnthalpy; // fluid from A
+ volA.Port.SpecificEnthalpy = volA.SpecificEnthalpy; // outflow carries its own enthalpy
+ }
+ else // B → A (mdot negative)
+ {
+ volA.Port.MassFlowRate = -mdot; // positive
+ volB.Port.MassFlowRate = mdot; // negative
+ volA.Port.SpecificEnthalpy = volB.SpecificEnthalpy; // fluid from B
+ volB.Port.SpecificEnthalpy = volB.SpecificEnthalpy; // outflow carries its own
+ }
+ }
+ }
+
+ // 3. Pipe‑volume boundary conditions – unchanged
foreach (var conn in _connections)
{
if (IsPipePort(conn.PortA) && IsVolumePort(conn.PortB))
@@ -29,11 +63,11 @@ namespace FluidSim.Core
SetVolumeBC(conn.PortB, conn.PortA);
}
- // 3. Run pipe simulations
+ // 4. Run pipe simulations
foreach (var p in _pipes)
p.Simulate();
- // 4. Transfer pipe‑port flows to volume ports
+ // 5. Transfer pipe‑to‑volume flows – unchanged
foreach (var conn in _connections)
{
if (IsPipePort(conn.PortA) && IsVolumePort(conn.PortB))
@@ -42,9 +76,21 @@ namespace FluidSim.Core
TransferPipeToVolume(conn.PortB, conn.PortA);
}
- // 5. Integrate volumes
+ // 6. Integrate volumes
foreach (var v in _volumes)
v.Integrate();
+
+ // 7. COMPUTE AUDIO SAMPLE from all sound connections
+ double sample = 0f;
+ foreach (var conn in _connections)
+ {
+ if (conn is SoundConnection)
+ {
+ // Both ports have the same absolute mass flow; either works.
+ sample += SoundProcessor.ComputeSample(conn);
+ }
+ }
+ LastSample = (float)Math.Tanh(sample);
}
bool IsVolumePort(Port p) => _volumes.Exists(v => v.Port == p);
diff --git a/Core/SoundEngine.cs b/Core/SoundEngine.cs
deleted file mode 100644
index bab240a..0000000
--- a/Core/SoundEngine.cs
+++ /dev/null
@@ -1,131 +0,0 @@
-using SFML.Audio;
-using SFML.System;
-
-namespace FluidSim;
-
-#region Lock‑free ring buffer (unchanged)
-internal class RingBuffer
-{
- private readonly float[] buffer;
- private volatile int readPos;
- private volatile int writePos;
-
- public RingBuffer(int capacity)
- {
- if ((capacity & (capacity - 1)) != 0)
- throw new ArgumentException("Capacity must be a power of two.");
- buffer = new float[capacity];
- }
-
- public int Count => (writePos - readPos) & (buffer.Length - 1);
- public int Space => (readPos - writePos - 1) & (buffer.Length - 1);
-
- public int Write(float[] data, int count)
- {
- int space = Space;
- int toWrite = Math.Min(count, space);
- int mask = buffer.Length - 1;
- for (int i = 0; i < toWrite; i++)
- buffer[(writePos + i) & mask] = data[i];
- writePos = (writePos + toWrite) & mask;
- return toWrite;
- }
-
- public int Read(float[] destination, int count)
- {
- int available = Count;
- int toRead = Math.Min(count, available);
- int mask = buffer.Length - 1;
- for (int i = 0; i < toRead; i++)
- destination[i] = buffer[(readPos + i) & mask];
- readPos = (readPos + toRead) & mask;
- return toRead;
- }
-}
-#endregion
-
-#region Stereo stream that consumes the ring buffer
-internal class RingBufferStream : SoundStream
-{
- private readonly RingBuffer ringBuffer;
-
- public RingBufferStream(RingBuffer buffer)
- {
- ringBuffer = buffer;
- // 2 channels, 44.1 kHz, standard stereo mapping
- Initialize(2, 44100, new[] { SoundChannel.FrontLeft, SoundChannel.FrontRight });
- }
-
- protected override bool OnGetData(out short[] samples)
- {
- const int monoBlockSize = 512; // number of mono samples we'll read
- float[] temp = new float[monoBlockSize];
- int read = ringBuffer.Read(temp, monoBlockSize);
- samples = new short[monoBlockSize * 2];
-
- if (read > 0)
- {
- for (int i = 0; i < read; i++)
- {
- float clamped = Math.Clamp(temp[i], -1f, 1f);
- short final = (short)(clamped * short.MaxValue);
- samples[i * 2] = final; // left
- samples[i * 2 + 1] = final; // right
- }
- }
- for (int i = read * 2; i < samples.Length; i++)
- samples[i] = 0;
-
- return true;
- }
-
- protected override void OnSeek(Time timeOffset) =>
- throw new NotSupportedException();
-}
-#endregion
-
-#region Public sound engine API (unchanged)
-public class SoundEngine : IDisposable
-{
- private readonly RingBuffer ringBuffer;
- private readonly RingBufferStream stream;
- private bool isPlaying;
-
- public SoundEngine(int bufferCapacity = 16384)
- {
- ringBuffer = new RingBuffer(bufferCapacity);
- stream = new RingBufferStream(ringBuffer);
- }
-
- public void Start()
- {
- if (isPlaying) return;
- stream.Play();
- isPlaying = true;
- }
-
- public void Stop()
- {
- if (!isPlaying) return;
- stream.Stop();
- isPlaying = false;
- float[] drain = new float[ringBuffer.Count];
- ringBuffer.Read(drain, drain.Length);
- }
-
- public int WriteSamples(float[] data, int count) =>
- ringBuffer.Write(data, count);
-
- public float Volume
- {
- get => stream.Volume;
- set => stream.Volume = value;
- }
-
- public void Dispose()
- {
- Stop();
- stream.Dispose();
- }
-}
-#endregion
\ No newline at end of file
diff --git a/Program.cs b/Program.cs
index 938ced0..a07b687 100644
--- a/Program.cs
+++ b/Program.cs
@@ -2,7 +2,8 @@
using SFML.Window;
using SFML.System;
using System.Diagnostics;
-using FluidSim.Core;
+using FluidSim.Scenarios;
+using FluidSim.Audio;
namespace FluidSim;
@@ -10,6 +11,8 @@ public class Program
{
private const int SampleRate = 44100;
private static volatile bool running = true;
+ // Global step counter – incremented every simulation step
+ private static long stepCount = 0;
public static void Main()
{
@@ -22,47 +25,71 @@ public class Program
soundEngine.Volume = 70;
soundEngine.Start();
- double lastAudioTime = 0.0;
var stopwatch = Stopwatch.StartNew();
- int warmupSamples = SampleRate / 2;
+ // --- Warmup: fill audio buffer with silence ---
+ int warmupSamples = SampleRate / 2; // 0.5 s
float[] warmup = new float[warmupSamples];
for (int i = 0; i < warmupSamples; i++)
warmup[i] = 0;
-
soundEngine.WriteSamples(warmup, warmupSamples);
- lastAudioTime = stopwatch.Elapsed.TotalSeconds;
+
+ // Reset timer after warmup – this is the “real‑time zero”
+ stopwatch.Restart();
+ stepCount = 0; // simulation steps start now
+
+ // --- Initialise the simulation scenario ---
+ Simulation.Initialize(SampleRate);
const int chunkSize = 2048;
float[] buffer = new float[chunkSize];
- Simulation.Initialize(SampleRate);
+ double lastLogTime = 0.0; // for periodic speed printout
while (window.IsOpen)
{
window.DispatchEvents();
+ // --- Compute how many audio samples are needed since last frame ---
double currentTime = stopwatch.Elapsed.TotalSeconds;
- double elapsed = currentTime - lastAudioTime;
- int samplesNeeded = (int)(elapsed * SampleRate);
+ double elapsed = currentTime; // since stopwatch was reset
+ int samplesNeeded = (int)(elapsed * SampleRate) - (int)(stepCount);
+ // (stepCount is total generated samples, so we just need the remainder)
+ // --- Generate the required number of simulation steps ---
while (samplesNeeded > 0 && running)
{
int toGenerate = Math.Min(samplesNeeded, chunkSize);
for (int i = 0; i < toGenerate; i++)
{
buffer[i] = Simulation.Process();
+ stepCount++;
}
soundEngine.WriteSamples(buffer, toGenerate);
samplesNeeded -= toGenerate;
}
- lastAudioTime = currentTime;
+ // --- Display speed ---
+ double simTime = stepCount / (double)SampleRate;
+ double wallTime = stopwatch.Elapsed.TotalSeconds;
+ double speed = (wallTime > 0) ? simTime / wallTime : 0.0;
+ // Update window title with instant speed
+ window.SetTitle($"FluidSim | Speed: {speed:F3}× | Steps: {stepCount}");
+
+ // Console log once per second
+ if (wallTime - lastLogTime >= 1.0)
+ {
+ Console.WriteLine($"Speed: {speed:F3}× ({stepCount} steps, {wallTime:F2}s wall)");
+ lastLogTime = wallTime;
+ }
+
+ // --- Rendering (placeholder) ---
window.Clear(Color.Black);
window.Display();
}
+ // --- Cleanup ---
soundEngine.Dispose();
window.Dispose();
}
diff --git a/Scenarios/Simulation.cs b/Scenarios/Simulation.cs
new file mode 100644
index 0000000..80dc89d
--- /dev/null
+++ 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");
+ }
+ }
+ }
+}
\ No newline at end of file
diff --git a/Sources/EffortSource.cs b/Sources/EffortSource.cs
deleted file mode 100644
index 78e186c..0000000
--- a/Sources/EffortSource.cs
+++ /dev/null
@@ -1,10 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Text;
-
-namespace FluidSim.Sources
-{
- internal class EffortSource
- {
- }
-}
diff --git a/Sources/FlowSource.cs b/Sources/FlowSource.cs
deleted file mode 100644
index 2004336..0000000
--- a/Sources/FlowSource.cs
+++ /dev/null
@@ -1,10 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Text;
-
-namespace FluidSim.Sources
-{
- internal class FlowSource
- {
- }
-}
diff --git a/Utils/Units.cs b/Utilities/Units.cs
similarity index 95%
rename from Utils/Units.cs
rename to Utilities/Units.cs
index b151478..bade8e6 100644
--- a/Utils/Units.cs
+++ b/Utilities/Units.cs
@@ -1,6 +1,4 @@
-using System;
-
-namespace FluidSim.Utils
+namespace FluidSim.Utilities
{
public static class Units
{