Flute acoustics: measurement, modelling and design - School of ...

APPENDIX B. PROGRAM LISTINGS 325
comprising the hole and matching length */
holeMatrix = tubeMatrix(f, hole->c, hole->rho, t, b, 1);
/* calculate the load (radiation) impedance of the hole */
if (strcmp(hole->fingering, "CLOSED") == 0)
Z_L = (hole->key == NULL) ?
closedFingerHoleLoadZ(f, hole) :
closedKeyedHoleLoadZ(f, hole);
else
Z_L = (hole->key == NULL) ?
openFingerHoleLoadZ(f, hole) :
openKeyedHoleLoadZ(f, hole);
}
return calcZin(holeMatrix, Z_L);
complex closedFingerHoleLoadZ(double f, Hole hole) {
double a = hole->boreRadius;
double b = hole->radius;
double delta = b / a;
double t_finger;
double Z0 = charZ(hole->c, hole->rho, hole->radius).Re;
double k = (2*M_PI*f)/hole->c;
t_finger = CORR_CLOSED_FINGER_HOLE_LENGTH * delta * b;
}
return imaginary(-Z0 / tan(k * t_finger));
complex closedKeyedHoleLoadZ(double f, Hole hole) {
double b = hole->radius;
double t_keypad;
double Z0 = charZ(hole->c, hole->rho, hole->radius).Re;
double k = (2*M_PI*f)/hole->c;
t_keypad = CORR_CLOSED_KEYED_HOLE_LENGTH * b;
if (t_keypad == 0) return inf;
return imaginary(-Z0 / tan(k * t_keypad));
}
complex openFingerHoleLoadZ(double f, Hole hole) {
double a, b, k;
complex Z_flanged, Z0, d_flanged, d_cyl, Z;
/* a is the radius of the hole */
a = hole->radius;
/* b is the radius of the (cylindrical) flange */
b = hole->boreRadius + hole->length;
/* calculate the wavenumber */
k = (2*M_PI*f)/hole->c;
/* calculate the characteristic impedance */
Z0 = charZ(hole->c, hole->rho, a);
/* calculate the impedance of the (infinitely) flanged hole */
Z_flanged = flangedZ(f, hole->c, hole->rho, a);