Adding ISO 9613 header of air absorption / atmospheric attenuation

CMakeLists.txt

@@ -75,10 +75,11 @@ set( ITABaseHeader
 	"include/ITAFastMath.h"
 	"include/ITAFileSystemUtils.h"
 	"include/ITAFiniteImpulseResponse.h"
+	"include/ITAFunctors.h"
 	"include/ITAHDFTSpectra.h"
 	"include/ITAHDFTSpectrum.h"
-	"include/ITAFunctors.h"
 	"include/ITAInterpolation.h"
+	"include/ITAISO9613.h"
 	"include/ITALog.h"
 	"include/ITAMagnitudeSpectrum.h"
 	"include/ITAMultichannelFiniteImpulseResponse.h"
@@ -115,6 +116,7 @@ set( ITABaseSources
 	"src/ITAHDFTSpectra.cpp"
 	"src/ITAHDFTSpectrum.cpp"
 	"src/ITAInterpolation.cpp"
+	"src/ITAISO9613.cpp"
 	"src/ITALog.cpp"
 	"src/ITAMagnitudeSpectrum.cpp"
 	"src/ITAMultichannelFiniteImpulseResponse.cpp"

include/ITAISO9613.h

+/*
+ * ----------------------------------------------------------------
+ *
+ *		ITA core libs
+ *		(c) Copyright Institute of Technical Acoustics (ITA)
+ *		RWTH Aachen University, Germany, 2015-2018
+ *
+ * ----------------------------------------------------------------
+ *				    ____  __________  _______
+ *				   //  / //__   ___/ //  _   |
+ *				  //  /    //  /    //  /_|  |
+ *				 //  /    //  /    //  ___   |
+ *				//__/    //__/    //__/   |__|
+ *
+ * ----------------------------------------------------------------
+ *
+ */
+
+#ifndef INCLUDE_WATCHER_ITA_ISO_9613
+#define INCLUDE_WATCHER_ITA_ISO_9613
+
+// ITABase
+#include <ITABaseDefinitions.h>
+#include <ITAThirdOctaveMagnitudeSpectrum.h>
+
+#include <string>
+
+namespace ITABase
+{
+	namespace ISO9613
+	{
+		//! Calculates the atmospheric absorption after ISO 9613-1 for one frequency in decibels
+		/**
+		  * Standard: ISO 9613-1:1993
+		  *
+		  * \param dFrequency Base frequency [Hz]
+		  * \param fDistance Distance [m]
+		  * \param fTemperature Temperature [C]
+		  * \param fStaticPressure Static air pressure [Pa]
+		  * \param fHumidity Relative humidity [%]
+		  *
+		  * @return Atmospheric absorption in dB
+		  */
+		double AtmosphericAbsorption( double dFrequency, double dDistance, double dTemperature, double dStaticPressure, double dHumidity );
+
+		//! Calculates the atmospheric absorption after ISO 9613-1: A_{atm} (formula 8) in decibels
+		/**
+		  * Standard: ISO 9613-1:1993
+		  *
+		  * \param oA_atm_dB Third-octave magnitude spectrum with atmospheric attenuation values in decibel
+		  * \param fDistance Distance [m]
+		  * \param fTemperature Temperature [C]
+		  * \param fStaticPressure Static air pressure [Pa]
+		  * \param fHumidity Relative humidity [%]
+		  */
+		void AtmosphericAbsorption( ITABase::CThirdOctaveDecibelMagnitudeSpectrum& oA_atm_dB, double dDistance, double dTemperature, double dStaticPressure, double dHumidity );
+
+		//! Calculates the atmospheric absorption in linear factors (instead of decibels)
+		void AtmosphericAbsorption( ITABase::CThirdOctaveFactorMagnitudeSpectrum& oA_atm_factor, double dDistance, double dTemperature, double dStaticPressure, double dHumidity );
+
+	}
+}
+
+#endif // INCLUDE_WATCHER_ITA_ISO_9613

src/ITAISO9613.cpp

+#include <ITAISO9613.h>
+
+#include <ITAConstants.h>
+#include <ITAException.h>
+#include <ITAThirdOctaveMagnitudeSpectrum.h>
+
+#include <cassert>
+
+using namespace ITABase;
+using namespace ISO9613;
+
+void AtmosphericAbsorption( ITABase::CThirdOctaveDecibelMagnitudeSpectrum& oA_atm_dB, double dDistance, double dTemperature, double dStaticPressure, double dHumidity )
+{
+	// @todo schleife ber freqs
+}
+
+double AtmosphericAbsorption( double dFrequency, double dDistance, double dTemperature, double dStaticPressure, double dHumidity )
+{
+	// ISO 9613-1 Acoustics - Attenuation of sound during propagation outdoors
+
+	// Noch nicht fertig ....
+	ITA_EXCEPT0( NOT_IMPLEMENTED );
+
+	// Reference ambient atmospheric pressure (Standard Ambient Atmosphere) [kPa] 
+	// (Referenzatmosphrendruck Umgebung nach ISO Standard)
+	const double p_r = 101.325f;
+	const double p_a = 101.325f;
+
+	// Inital sound pressure amplitude [kPa]
+	const double p_i = p_r + 0.0f;
+
+	// Sound pressure amplitude [Pa]
+	const double p_t = 1.0f;
+
+	// Reference air temperature [K]
+	const double T_0 = 273.15f + 20.0f;
+
+	// Temperature [K]
+	const double T = 273.15f + dTemperature;
+
+	// Molar concentration dry air
+	const double tmp = ( 10.79586f * ( 1.0f - ( ( T_0 - 20.0f ) / T ) ) ) -
+		( 5.02808f * log10( ( T / ( T_0 - 20.0f ) ) ) ) +
+		( 1.50474f * 0.0001f * ( 1.0f - pow( ( double ) 10.0f, ( -8.29692f*( ( T / ( T_0 - 20.0f ) ) - 1.0f ) ) ) ) ) +
+		( 0.42873f * 0.001f * ( -1.0f + pow( ( double ) 10.0f, ( -4.76955f*( 1.0f - ( ( T_0 - 20.0f ) / T ) ) ) ) ) ) -
+		2.2195983f;
+
+	// Molar concentration of water vapour [%] (Molekldichte Wasserdampf)
+	assert( 0.0f <= dHumidity && dHumidity <= 100.0f );
+	const double h = dHumidity * pow( ( double ) 10.0f, tmp ) / ( p_a / p_r );
+
+	// Equation (3)
+	const double f_r_o = ( p_a / p_r ) * ( 24.0f + 4.04f*10.0e4*h*( 0.02f + h ) / ( 0.391f + h ) );
+
+	// Equation (4)
+	const double f_r_n = ( p_a / p_r ) * pow( T / T_0, ( double ) -1.0f / 2.0f ) * ( 9.0f + 280.0f*h*exp( -4.710f * ( pow( T / T_0, ( double ) -( 1 / 3.0f ) ) - 1.0f ) ) );
+
+
+	// Parts of Equation (5)
+	double dAlpha1 = 8.686f * pow( dFrequency, ( double ) 2.0f );
+	double dAlpha2 = 1.84f * 10e-11 * pow( p_a / p_r, ( double ) -1.0f ) * pow( T / T_0, ( double ) -1.0f / 2.0f );
+	double dAlpha3 = pow( T / T_0, ( double ) -5.0f / 2.0f );
+	double dAlpha4 = 0.01275f * exp( -2239.1f / T ) * pow( f_r_o + pow( dFrequency, ( double ) 2.0f ) / f_r_o, ( double ) -1.0f );
+	double dAlpha5 = 0.10680f * exp( -3352.0f / T ) * pow( f_r_n + pow( dFrequency, ( double ) 2.0f ) / f_r_n, ( double ) -1.0f );
+
+	// Attenuation coefficient [dB/m], ~f, as assembly of Equation (5) parts
+	double dAlpha = dAlpha1 * ( dAlpha2 + dAlpha3 * ( dAlpha4 + dAlpha5 ) );
+
+	// Resulting attenuation [dB], ~alpha (~f)
+	double dAttenuationAirAbsorptionDecibel = dAlpha * dDistance;
+
+	// Attenuation factor in decibel
+	return dAttenuationAirAbsorptionDecibel;
+}
\ No newline at end of file