JUNESCO.hh

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#ifndef __JACOUSTICS__JUNESCO__
#define __JACOUSTICS__JUNESCO__

/**
 * \file
 *
 * Sound velocity according UNESCO equation.
 * \author mdejong
 */
namespace JACOUSTICS {}
namespace JPP { using namespace JACOUSTICS; }

namespace JACOUSTICS {

  /**
   * Get sound velocity according UNESCO equation.
   * K.V. Mackenzie, Nine-term equation for the sound speed in the oceans (1981)\n
   * J. Acoust. Soc. Am. 70(3), pp 807-812
   *
   * \param  D            Depth [m]
   * \param  S            Salinity [ppk]
   * \param  T            Temperature [C]
   * \return              sound velocity [m/s]
   */
  inline double getVelocityMackenzie(const double D, const double S, const double T)
  {
    return (1448.96
            + 4.591 * T
            - 5.304e-2  * T*T
            + 2.374e-4  * T*T*T
            + 1.340 * (S - 35)
            + 1.630e-2  * D
            + 1.675e-7  * D*D
            - 1.025e-2  * T * (S - 35)
            - 7.139e-13 * T*D*D*D);
  }



  /**
   * Get sound velocity according UNESCO equation.
   * A.B. Coppens, Simple equations for the speed of sound in Neptunian waters (1981)\n
   * J. Acoust. Soc. Am. 69(3), pp 862-863
   *
   * \param  D            Depth [m]
   * \param  S            Salinity [ppk]
   * \param  T            Temperature [C]
   * \return              sound velocity [m/s]
   */
  inline double getVelocityCoppens(const double D, const double S, const double T)
  {
    const double t = T * 0.1;
    const double d = D * 1.0e-3;
    const double c = 1449.05 + 45.7 * t - 5.21 * t*t + 0.23 * t*t*t + (1.333 - 0.126*t + 0.009 * t*t)*(S - 35);

    return (c + 
            (16.23 + 0.253*t) * d    + 
            (0.213 - 0.1*t)   * d*d  + 
            (0.016 + 0.0002*(S-35))*(S - 35)*t*d);
  }


  /**
   * Get sound velocity according UNESCO equation ().
   *
   * \param  D            Depth [m]
   * \param  S            Salinity [ppk]
   * \param  T            Temperature [C]
   * \return              sound velocity [m/s]
   */
  inline double getVelocity(const double D, const double S, const double T)
  {
    return getVelocityMackenzie(D, S, T);
  }
}

#endif