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

APPENDIX B. PROGRAM LISTINGS 195
/*
Acoustics.c
By Paul Dickens, 2005
Listing B.2: Acoustics.c
Acoustics library.
Refer to Acoustics.h for interface details.
*/
#include
#include
#include "Acoustics.h"
#include "Complex.h"
double saturationVapourPressureWater(double T) {
double C1, C2, C3, C4;
C1 = 1.2811805e-5;
C2 = 1.9509874e-2;
C3 = 34.04926034;
C4 = 6.3536311e3;
return exp(C1*pow(T,2) - C2*T + C3 - C4/T);
}
double speedSound(double t, double p, double h, double x_c) {
double f, T, p_sv, x_w;
/* Calculate mole fraction of water vapour using equation in Cramer
Appendix (p. 2515) */
f = 1.00062 + 3.14e-8*p + 5.6e-7*pow(t,2);
T = t + 273.15;
p_sv = saturationVapourPressureWater(T);
x_w = h*f*p_sv/p;
return speedSoundCramer(t,p,x_w,x_c);
}
double speedSoundCramer(double t, double p, double x_w, double x_c) {
int i;
double c = 0;
double a[] = {
331.5024,
0.603055,
-0.000528,
51.471935,
0.1495874,
-0.000782,
-1.82e-7,
3.73e-8,
-2.93e-10,
-85.20931,
-0.228525,
5.91e-5,
-2.835149,
-2.15e-13,
29.179762,
0.000486
};
double coeff[] = {