Speed of Sound in Fluids (Newton-Laplace equation )


The speed of sound is the distance travelled per unit of time by a sound wave propagating through an elastic medium.
Sound travels faster in liquids and non-porous solids than it does in air. The speed of a compression wave in fluid is determined by the medium’s compressibility and density.
The speed of sound increases with the stiffness (the resistance of an elastic body to deformation by an applied force) of the material, and decreases with the density. In a fluid the only non-zero stiffness is to volumetric deformation (a fluid does not sustain shear forces).
In general, the speed of sound c is given by the Newton-Laplace equation

Related formulas


cfluidspeed of sound for fluids (m/s)
Kbulk modulus of the fluid (pascal)
ρfluid density (kg/m3)