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max
2026-06-09 17:49:11 +02:00
parent 1489f278dc
commit 21a62fb46e
6 changed files with 401 additions and 192 deletions
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116
Core/BoundarySystem.cs
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@@ -165,7 +165,7 @@ namespace FluidSim.Core
continue;
}
// ---- Preliminary isentropic solution (used for face pressure if inertance is on) ----
// ---- Preliminary isentropic solution ----
float mdotEst, rhoFaceEst, uFaceEst, pFaceEst;
if (volP >= pipeP)
{
@@ -179,7 +179,7 @@ namespace FluidSim.Core
mdotEst = -mdotEst;
}
// ---- Compute ghost state ----
// ---- Compute final mass flow with limiters ----
float mdotFinal, rhoFace, uFace, pFace, airFracGhost;
if (d.UseInertance)
@@ -189,11 +189,10 @@ namespace FluidSim.Core
float dp = volP - pipeP;
float Rlin = d.LossCoefficient;
// Forward Euler
float dmdot_dt = (dp - Rlin * d.CurrentMdot) / MathF.Max(inertance, 1e-12f);
float mdotNew = d.CurrentMdot + dmdot_dt * dt;
// ---------- Symmetric flow limiters (existing) ----------
// Limit outflow from volume (if volume owner is Volume0D)
if (d.VolumePort.Owner is Volume0D vol0)
{
float maxOut = vol0.Mass / dt;
@@ -201,15 +200,19 @@ namespace FluidSim.Core
if (mdotNew < -maxOut) mdotNew = -maxOut;
}
int adjCell = d.IsLeftEnd ? _pipeSystem.GetPipeStart(d.PipeIndex)
: _pipeSystem.GetPipeEnd(d.PipeIndex) - 1;
float pipeRhoAdj = _pipeSystem.GetCellDensity(adjCell);
float pipeDxAdj = _pipeSystem.GetCellDx(adjCell);
float pipeCellMass = pipeRhoAdj * area * pipeDxAdj;
float maxFromPipe = pipeCellMass / dt;
if (mdotNew < -maxFromPipe) mdotNew = -maxFromPipe;
// Limit inflow from pipe – pipe cell cannot be emptied in one step
{
int adjCell = d.IsLeftEnd ? _pipeSystem.GetPipeStart(d.PipeIndex)
: _pipeSystem.GetPipeEnd(d.PipeIndex) - 1;
float pipeRhoAdj = _pipeSystem.GetCellDensity(adjCell);
float pipeAreaCell = _pipeSystem.GetCellArea(adjCell); // true cell area, not orifice
float pipeDxAdj = _pipeSystem.GetCellDx(adjCell);
float pipeCellMass = pipeRhoAdj * pipeAreaCell * pipeDxAdj;
float maxFromPipe = pipeCellMass / dt;
if (mdotNew < -maxFromPipe) mdotNew = -maxFromPipe;
}
// ---------- Velocity clamp to Mach 0.9 ----------
// Velocity clamp to Mach 0.9
float rhoFacePrelim = mdotNew >= 0 ? volRho : pipeRho;
float uFacePrelim = MathF.Abs(mdotNew) / MathF.Max(rhoFacePrelim * area, 1e-12f);
float cUp = mdotNew >= 0 ? MathF.Sqrt(Gamma * Rgas * volT) : MathF.Sqrt(Gamma * Rgas * pipeT);
@@ -220,46 +223,64 @@ namespace FluidSim.Core
mdotNew = rhoFacePrelim * uFacePrelim * area * (mdotNew >= 0 ? 1f : -1f);
}
// NaN safety
if (float.IsNaN(mdotNew)) mdotNew = 0f;
d.CurrentMdot = mdotNew;
mdotFinal = mdotNew;
// Ghost state
rhoFace = mdotFinal >= 0 ? volRho : pipeRho;
pFace = pFaceEst;
uFace = MathF.Abs(mdotFinal) / MathF.Max(rhoFace * area, 1e-12f);
}
else
{
// ---- Standard quasi‑steady orifice ----
// Standard quasi‑steady orifice
mdotFinal = mdotEst;
rhoFace = rhoFaceEst;
uFace = uFaceEst;
pFace = pFaceEst;
// Limit outflow from cavity
// Limit outflow from volume (if Volume0D)
if (d.VolumePort.Owner is Volume0D vol0)
{
float maxOut = vol0.Mass / dt;
if (mdotFinal > maxOut) mdotFinal = maxOut;
}
// ***** CRITICAL: Limit inflow from pipe – pipe cell cannot be drained *****
if (mdotFinal < 0)
{
int adjCell = d.IsLeftEnd ? _pipeSystem.GetPipeStart(d.PipeIndex)
: _pipeSystem.GetPipeEnd(d.PipeIndex) - 1;
float pipeRhoAdj = _pipeSystem.GetCellDensity(adjCell);
float pipeAreaCell = _pipeSystem.GetCellArea(adjCell);
float pipeDxAdj = _pipeSystem.GetCellDx(adjCell);
float pipeCellMass = pipeRhoAdj * pipeAreaCell * pipeDxAdj;
float maxFromPipe = pipeCellMass / dt;
if (mdotFinal < -maxFromPipe)
mdotFinal = -maxFromPipe;
}
d.CurrentMdot = mdotFinal;
// Limit outflow from cylinder into pipe (positive mdot = volume → pipe)
if (mdotFinal > 0f && d.VolumePort?.Owner is Cylinder cyl)
{
float maxOut = cyl.Mass / dt;
if (mdotFinal > maxOut)
mdotFinal = maxOut;
}
}
// ---- Determine air fraction for ghost ----
// ---- Air fraction for ghost ----
if (mdotFinal >= 0)
{
airFracGhost = volAF;
}
else
{
airFracGhost = pipeAF;
if (d.VolumePort != null) d.VolumePort.AirFraction = pipeAF;
}
// ---- Apply sign convention for velocity ----
// ---- Sign convention for velocity ----
if (mdotFinal >= 0 && d.IsLeftEnd) uFace = +uFace;
else if (mdotFinal >= 0 && !d.IsLeftEnd) uFace = -uFace;
else if (mdotFinal < 0 && d.IsLeftEnd) uFace = -uFace;
@@ -271,18 +292,17 @@ namespace FluidSim.Core
else
_pipeSystem.SetGhostRight(d.PipeIndex, rhoFace, uFace, pFace, airFracGhost);
// ---- Update volume port (mass flow: positive into volume) ----
// ---- Update volume port ----
if (d.VolumePort != null)
{
d.VolumePort.MassFlowRate = -mdotFinal;
// Set enthalpy of the stream entering the volume
if (-mdotFinal >= 0) // mass flowing into the volume (out of pipe)
if (-mdotFinal >= 0) // mass entering volume (out of pipe)
{
float pipeH = GammaOverGm1 * pipeP / MathF.Max(pipeRho, 1e-12f);
d.VolumePort.SpecificEnthalpy = pipeH;
}
else // mass flowing out of the volume (into pipe)
else // mass leaving volume (into pipe)
{
d.VolumePort.SpecificEnthalpy = volH;
}
@@ -309,6 +329,7 @@ namespace FluidSim.Core
float cInt = MathF.Sqrt(gamma * pInt / MathF.Max(rhoInt, 1e-12f));
float pAmb = d.AmbientPressure;
// Characteristic solution (isentropic expansion to ambient)
float Jplus = uInt + 2f * cInt / gm1;
float Jminus = uInt - 2f * cInt / gm1;
float s = pInt / MathF.Pow(rhoInt, gamma);
@@ -318,9 +339,14 @@ namespace FluidSim.Core
? (Jminus + 2f * cIso / gm1)
: (Jplus - 2f * cIso / gm1);
// Supersonic check
bool supersonic = d.IsLeftEnd ? (uInt <= -cInt) : (uInt >= cInt);
float rhoGhost, uGhost, pGhost, afGhost;
if (!supersonic)
{
supersonic = d.IsLeftEnd ? (uIso <= -cIso) : (uIso >= cIso);
}
float rhoGhost, uGhost, pGhost, afGhost;
if (supersonic)
{
rhoGhost = rhoInt; uGhost = uInt; pGhost = pInt; afGhost = afInt;
@@ -332,15 +358,45 @@ namespace FluidSim.Core
afGhost = inflow ? 1f : afInt;
}
// ------- Mass flow limiter -------
int adjCell = d.IsLeftEnd
? _pipeSystem.GetPipeStart(d.PipeIndex)
: _pipeSystem.GetPipeEnd(d.PipeIndex) - 1;
float pipeRhoAdj = _pipeSystem.GetCellDensity(adjCell);
float pipeAreaCell = _pipeSystem.GetCellArea(adjCell);
float pipeDxAdj = _pipeSystem.GetCellDx(adjCell);
float cellMass = pipeRhoAdj * pipeAreaCell * pipeDxAdj;
float area = d.PipeArea;
float mdotRaw = rhoGhost * uGhost * area; // positive out of pipe
if (d.IsLeftEnd) mdotRaw = -mdotRaw; // now positive = out of pipe
// Outflow limit
if (mdotRaw > 0 && mdotRaw * dt > cellMass)
{
mdotRaw = cellMass / dt;
}
// Inflow limit (allow up to 10× cell mass to avoid starving the pipe)
else if (mdotRaw < 0 && -mdotRaw * dt > 10f * cellMass)
{
mdotRaw = -10f * cellMass / dt;
}
// Recompute uGhost from the limited mdot, keeping rhoGhost, pGhost
float mdotMag = MathF.Abs(mdotRaw);
uGhost = mdotMag / MathF.Max(rhoGhost * area, 1e-12f);
if (d.IsLeftEnd)
uGhost = (mdotRaw >= 0f) ? -uGhost : uGhost;
else
uGhost = (mdotRaw >= 0f) ? uGhost : -uGhost;
// Apply ghost
if (d.IsLeftEnd)
_pipeSystem.SetGhostLeft(d.PipeIndex, rhoGhost, uGhost, pGhost, afGhost);
else
_pipeSystem.SetGhostRight(d.PipeIndex, rhoGhost, uGhost, pGhost, afGhost);
float area = d.PipeArea;
float mdot = rhoGhost * uGhost * area;
if (d.IsLeftEnd) mdot = -mdot;
d.LastMassFlowRate = mdot;
d.LastMassFlowRate = mdotRaw;
d.LastFacePressure = pGhost;
}
}