# Acoustic impedance water surface in partially filled tank

1. Dec 8, 2015

### Ilias Aouaj

Hello guys,

Consider a partially filled tank with water where the acoustic field can be described by the Helmholtz equation.

The boundary condition at the water surface would be $$\frac{∂p}{∂\vec{n}} = -j\rho_0\omega\frac{p}{Z}$$
where Z is the impedance of the water surface.

What would be the impedance of the water surface.? Are there any models i could use?