Auxiliary data structure for calculation of attenuation length. More...

#include <JAcousticsSupportkit.hh>

Public Member Functions
	JAttenuationLength (const double T, const double S, const double pH)
	Constructor.

double	operator() (const double D_m, const double f_kHz) const
	Get attentuation length for given frequency at given depth.

Public Attributes
double	T

double	S

double	pH

Detailed Description

Auxiliary data structure for calculation of attenuation length.

Attenuation according to Ainslie and McColm, J. Acoust. Soc. AM. 103 (3) 1671 1998.
See also http://resource.npl.co.uk/acoustics/techguides/seaabsorption/physics.html for numerical values.

Definition at line 30 of file JAcousticsSupportkit.hh.

Constructor & Destructor Documentation

◆ JAttenuationLength()

JACOUSTICS::JAttenuationLength::JAttenuationLength	(	const double	T,
		const double	S,
		const double	pH )

inline

Constructor.

Parameters

T	temperature [C]
S	salinity [pm]
pH	pH

Definition at line 38 of file JAcousticsSupportkit.hh.

                                        :
      T (T),
      S (S),
      pH(pH)
    {}

Member Function Documentation

◆ operator()()

double JACOUSTICS::JAttenuationLength::operator()	(	const double	D_m,
		const double	f_kHz ) const

inline

Get attentuation length for given frequency at given depth.

Parameters

D_m	depth [m]
f_kHz	frequency [kHz]

Returns: attenuation length [m]

Definition at line 54 of file JAcousticsSupportkit.hh.

    {
      const double z  = D_m * 1.0e-3;
      const double f1 = 0.78    * sqrt(S/35.0) * exp(T/26.0);
      const double f2 = 42.0    * exp(T/17.0);
      const double a1 = 0.106   * f1*(f_kHz*f_kHz) / (f_kHz*f_kHz + f1*f1) * exp((pH-8.0)/0.56);
      const double a2 = 0.52    * (1.0 + T/43.0) * (S/35.0) * f2 * f_kHz*f_kHz / (f_kHz*f_kHz + f2*f2) * exp(-z/6.0);
      const double a0 = 0.00049 * exp(-T/27.0 + z/17.0) * f_kHz*f_kHz;
      const double A  = a0 + a1 + a2;  // dB/km
      
      return 10.0e3 / (A*log(10.0));
    }