Notation
Table 1 gives an outline of physical constants and also of quantities that are constant if the environment has constant pressure and temperature. A comprehensive reference for fundamental constants, data, and nomenclature in the field of chemistry and physics is Quack et al. Physical quantities used in AcoustoDict are listed in Table 2.
Symbol |
Quantity |
Value |
SI Units |
Comment |
|---|---|---|---|---|
speed of sound in air |
342.2 |
|||
|
dynamic viscosity of air |
1.825e–5 |
|
|
|
air equilibrium pressure |
101325 |
Pa |
|
|
Prandtl number of air |
0.702 |
1 |
|
|
air density |
1.204 |
|
|
|
environment temperature |
293 |
K |
|
|
specific heat ratio of air |
1.4 |
1 |
Table 1: Physical constants used in AcoustoDict.
Symbol |
Definition |
SI Units |
Comment |
|---|---|---|---|
sound absorption coefficient |
1 |
||
high frequency limit of tortuosity (tortuosity factor) |
1 |
||
thickness of porous medium |
m |
||
sound wave frequency |
|
||
dynamic bulk modulus |
Pa |
complex |
|
complex wave number |
|
complex |
|
|
permeability |
|
|
viscous characteristic length |
1 |
||
thermal characteristic length |
1 |
||
angular frequency |
|||
open porosity |
1 |
||
upscaled pressure at inlet/outlet |
Pa |
||
effective density |
complex |
||
sound pressure reflection coefficient |
1 |
complex |
|
static airflow resistivity |
|||
auxiliary variable |
1 |
||
characteristic impedance |
complex |
||
acoustic surface impedance |
purely imaginary |
