@Override
public double calcOutletPressure(double inletPres, double flowAccel) {
double dyn =
this.getDynamicPressure(); // Note that dynamic pressure is negative for negative velocities
double pres = inletPres;
pres -= this.getFluid().getDensityxGravity() * heightChangeInput.getValue();
if (Math.abs(dyn) > 0.0 && this.getFluid().getViscosity() > 0.0) {
this.setDarcyFrictionFactor();
pres -= darcyFrictionFactor * dyn * this.getLength() / this.getDiameter();
} else {
darcyFrictionFactor = 0.0;
}
pres -= pressureLossCoefficientInput.getValue() * dyn;
pres -= flowAccel * this.getFluid().getDensity() * lengthInput.getValue() / this.getFlowArea();
return pres;
}
@Override
protected double getNextSample() {
double u2, b, sample;
// Case 1 - Shape parameter < 1
if (shapeInput.getValue() < 1.0) {
double threshold;
b = 1.0 + (shapeInput.getValue() / Math.E);
do {
double p = b * rng2.nextUniform();
u2 = rng1.nextUniform();
if (p <= 1.0) {
sample = Math.pow(p, 1.0 / shapeInput.getValue());
threshold = Math.exp(-sample);
} else {
sample = -Math.log((b - p) / shapeInput.getValue());
threshold = Math.pow(sample, shapeInput.getValue() - 1.0);
}
} while (u2 > threshold);
}
// Case 2 - Shape parameter >= 1
else {
double u1, w, z;
double a = 1.0 / Math.sqrt((2.0 * shapeInput.getValue()) - 1.0);
b = shapeInput.getValue() - Math.log(4.0);
double q = shapeInput.getValue() + (1.0 / a);
double d = 1.0 + Math.log(4.5);
do {
u1 = rng1.nextUniform();
u2 = rng2.nextUniform();
double v = a * Math.log(u1 / (1.0 - u1));
sample = shapeInput.getValue() * Math.exp(v);
z = u1 * u1 * u2;
w = b + q * v - sample;
} while ((w + d - 4.5 * z < 0.0) && (w < Math.log(z)));
}
// Scale the sample by the desired mean value
return sample * meanInput.getValue() / shapeInput.getValue();
}
@Override
public HasScreenPoints.PointsInfo[] getScreenPoints() {
synchronized (screenPointLock) {
if (cachedPointInfo == null) {
cachedPointInfo = new HasScreenPoints.PointsInfo[1];
HasScreenPoints.PointsInfo pi = new HasScreenPoints.PointsInfo();
cachedPointInfo[0] = pi;
pi.points = pointsInput.getValue();
pi.color = colourInput.getValue();
pi.width = widthInput.getValue().intValue();
if (pi.width < 1) pi.width = 1;
}
return cachedPointInfo;
}
}
/*
* Return the Darcy Friction Factor for a turbulent flow.
*/
private double getTurbulentFrictionFactor(double reynoldsNumber) {
double x = 1.0; // The present value for x = 1 / sqrt( frictionfactor ).
double lastx = 0.0;
double a = (roughnessInput.getValue() / this.getDiameter()) / 3.7;
double b = 2.51 / reynoldsNumber;
int n = 0;
while (Math.abs(x - lastx) / lastx > 1.0e-10 && n < 20) {
lastx = x;
x = -2.0 * Math.log10(a + b * lastx);
n++;
}
if (n >= 20) {
error(
"Darcy Friction Factor iterations did not converge: lastx = %f x = %f n = %d",
lastx, x, n);
}
return 1.0 / (x * x);
}
@Override
protected double getStandardDeviation() {
return meanInput.getValue() / Math.sqrt(shapeInput.getValue());
}
@Override
protected double getMeanValue() {
return meanInput.getValue();
}
@Override
protected double getStandardDeviation() {
return meanInput.getValue();
}
@Override
protected double getNextSample() {
// Inverse transform method
return (-meanInput.getValue() * Math.log(rng.nextUniform()));
}
@Override
public double getLength() {
return lengthInput.getValue();
}