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If Linear elastic is selected, specify the Density ρ (SI unit: kg/m3). The default density uses values From material. For User defined enter a value or expression. The default is 1.2 kg/m3.
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The definition of the attenuation coefficient implemented in the Ray Acoustics interface results in an intensity that scales as I(x) = I0exp(−2αx), where x is the distance traveled (this is not including terms based on curvature) and I0 is the initial intensity. The factor 2α is sometimes referred to as the intensity absorption coefficient. In most room acoustics references this value is called the attenuation constant m. When setting up models it is important to know which definition is used and possibly divide the input data with 2, as α = m/2.
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If User-defined attenuation is selected, specify the Density ρ (SI unit: kg/m3). The default density uses values From material. For User defined enter a value or expression. The default is 1.2 kg/m3. Enter a value or expression for the Attenuation coefficient α (SI unit: 1/m). Do not confuse this coefficient with the attenuation constant m most often defined in room acoustics (also known as the intensity attenuation coefficient). The two are related through 2α = m.
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For Ocean attenuation enter the following:
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Temperature T (SI unit: K) in the Model Inputs section. This can be User defined or taken from the Common model input. For User defined the default is 293.15 K.
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Practical salinity Sp (dimensionless) in the Model Inputs section. This can be User defined or taken from the Common model input. For User defined the default is 0.
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Depth D (SI unit: m) in the Model Inputs section. This can be User defined or taken from the Common model input. For User defined the default is 0.
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pH value pH (dimensionless). The default is 8.
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For Atmosphere attenuation enter the following:
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Temperature T (SI unit: K) in the Model Inputs section. This can be User defined or taken from the Common model input. For User defined the default is 293.15 K.
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Absolute pressure pA (SI unit: Pa) in the Model Inputs section. This can be User defined or taken from the Common model input. For User defined the default is 1 atm.
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Relative humidity (dimensionless) in the Model Inputs section. This can be User defined or taken from the Common model input. For User defined the default is 0.
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If Thermally conducting and viscous is selected, specify the following material properties. By default, all fluid properties take default values From material. Choose User defined to enter a value or expression for the:
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Thermal conductivity k (SI unit: W/(m·K)). The default value is 0.0257 W/(m·K). For ray acoustics, the thermal conductivity is assumed to be isotropic.
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