Wavenumber - Knowlpedia

For a wavevector $k$ , the angular wavenumber is $|k|$ , its Euclidean length. It measures spatial phase variation in radians per unit distance. In one dimension authors may instead use a signed wavenumber; the convention must be stated.

Frequency parameters

For $e^{i\kappa\Phi}$ , the local wavenumber is $|\kappa|\,|\nabla\Phi|$ , not merely $|\kappa|$ . If $\nabla\Phi$ changes along a flow, viscous damping changes even when the carrier parameter $\kappa$ is fixed.