@Test
public final void testCone() {
try {
PhysicalParameters parameters = new PhysicalParameters(25., TemperatureType.C);
double z0 = parameters.calcZ0(BaseRadius);
double waveNumber = parameters.calcWaveNumber(BaseFrequency);
TerminationCalculator term = new IdealOpenEndCalculator();
StateVector sv = term.calcStateVector(null, waveNumber, parameters);
TransferMatrix tm =
Tube.calcConeMatrix(waveNumber, BaseLength, BaseRadius, 0.75 * BaseRadius, parameters);
assertEquals("Determinant incorrect", 1.0, tm.determinant().getReal(), 0.0001);
assertEquals("Determinant.imag incorrect", 0.0, tm.determinant().getImaginary(), 0.0001);
Complex zLoad = tm.multiply(sv).Impedance().divide(z0);
assertEquals("Re(Z) incorrect", 0.03871, zLoad.getReal(), 0.00001);
assertEquals("Im(Z) incorrect", -0.46038, zLoad.getImaginary(), 0.00001);
BoreSectionCalculator boreCalc = new DefaultBoreSectionCalculator();
BoreSection bore = new BoreSection(BaseLength, BaseRadius, 0.75 * BaseRadius);
TransferMatrix tm2 = boreCalc.calcTransferMatrix(bore, waveNumber, parameters);
assertEquals("Determinant 2 incorrect", 1.0, tm2.determinant().getReal(), 0.0001);
assertEquals("Determinant.imag 2 incorrect", 0.0, tm2.determinant().getImaginary(), 0.0001);
Complex zLoad2 = tm2.multiply(sv).Impedance().divide(z0);
assertEquals("Re(Z2) incorrect", 0.03871, zLoad2.getReal(), 0.00001);
assertEquals("Im(Z2) incorrect", -0.46038, zLoad2.getImaginary(), 0.00001);
} catch (Exception e) {
fail(e.getMessage());
}
}
/*
* (non-Javadoc)
*
* @see com.wwidesigner.geometry.HoleCalculator#calcTransferMatrix(double,
* com.wwidesigner.util.PhysicalParameters)
*/
@Override
public TransferMatrix calcTransferMatrix(
Hole hole, double waveNumber, PhysicalParameters parameters) {
mParams = parameters;
updateGeometry(hole);
TransferMatrix matrix = new TransferMatrix();
double omega = waveNumber * mParams.getSpeedOfSound();
double freq = omega / (2. * Math.PI);
double z0 = mParams.getRho() * mParams.getSpeedOfSound() / (Math.PI * mRB * mRB); // Wave
// impedance of
// the main
// bore.
double rb_on_rh = mRB / mRH;
double rb_on_rh_2 = rb_on_rh * rb_on_rh;
matrix.setPP(Complex.ONE);
matrix.setUU(Complex.ONE);
if (hole.isOpenHole()) {
// Sign as per Gordon's implementation
matrix.setPU(Complex.I.multiply(z0 * rb_on_rh_2 * waveNumber * mOHLB));
matrix.setUP(
new Complex(0., -1.)
.multiply(waveNumber * calcHLE(freq))
.add(calcXi(freq))
.multiply(z0 * rb_on_rh_2)
.reciprocal());
// Change sign to match Antoine's configuration
// matrix.setPU(new Complex(0., -1.).multiply(z0 * rb_on_rh_2 *
// waveNumber
// * mOHLB));
// matrix.setUP(new Complex(0., 1.)
// .multiply(waveNumber * calcHLE(freq)).add(calcXi(freq))
// .multiply(z0 * rb_on_rh_2).reciprocal());
} else {
// Sign as per Gordon's implementation
matrix.setPU(Complex.I.multiply(z0 * rb_on_rh_2 * waveNumber * mCHLB));
matrix.setUP(new Complex(0., -1.).multiply(Math.tan(waveNumber * mLH) / (z0 * rb_on_rh_2)));
// Change sign to match Antoine's configuration
// matrix.setPU(new Complex(0., -1.).multiply(z0 * rb_on_rh_2
// * waveNumber * mCHLB));
// matrix.setUP(new Complex(0., 1.).multiply(Math.tan(waveNumber
// * mLH)
// / (z0 * rb_on_rh_2)));
}
return matrix;
}
@Test
public final void testImpedance() {
try {
PhysicalParameters parameters = new PhysicalParameters(25., TemperatureType.C);
double z0 = parameters.calcZ0(BaseRadius);
Complex zLoad = Tube.calcZload(BaseFrequency, BaseRadius, parameters).divide(z0);
assertEquals("Re(Z) incorrect", 0.00101768, zLoad.getReal(), 1.0e-6);
assertEquals("Im(Z) incorrect", 0.039, zLoad.getImaginary(), 0.0001);
} catch (Exception e) {
fail(e.getMessage());
}
}
// Specific resistance along the bore, when the hole is open.
protected double calcXi(double freq) {
double omega = 2.0 * Math.PI * freq;
double k = omega / mParams.getSpeedOfSound(); // Wavenumber.
double d_v = Math.sqrt(2.0 * mParams.getEta() / (mParams.getRho() * omega));
// Viscous boundary layer thickness.
double alpha =
(Math.sqrt(2 * mParams.getEta() * omega / mParams.getRho())
+ (mParams.getGamma() - 1)
* Math.sqrt(
2. * mParams.getKappa() * omega / (mParams.getRho() * mParams.getC_p())))
/ (2. * mRH * mParams.getSpeedOfSound());
double result =
0.25 * (k * mRH) * (k * mRH) + alpha * mLH + 0.25 * k * d_v * Math.log(2. * mRH / mRC);
return result;
}
// Effective acoustic length of the hole when it is open.
protected double calcHLE(double freq) {
// See Keefe 1990
double k = 2.0 * Math.PI * freq / mParams.getSpeedOfSound(); // Wavenumber.
double k_inv = 1.0 / k;
double tan_k_l = Math.tan(k * mLH);
double rh_on_rb = mRH / mRB;
double result =
(k_inv * tan_k_l + mRH * (1.40 - 0.58 * rh_on_rb * rh_on_rb))
/ (1.0 - 0.61 * k * mRH * tan_k_l);
// From eq. (5) in Keefe (1990):
return result;
}