Welligkeiten

Welligkeiten is the German term for undulations or waviness. It denotes regular or semi-regular wave-like deviations in a line, surface, or signal, characterized by wavelength and amplitude. The term is used across disciplines to distinguish larger-scale, low-frequency deviations from finer irregularities.

In metrology, waviness is a component of surface texture that describes the larger-scale form deviations after removing high-frequency roughness. It is typically measured with profilometry and separated from roughness by applying a smoothing filter with a cutoff length. Specimens or manufactured parts are assessed for waviness to evaluate flatness and functional fit.

In geology and earth sciences, Welligkeiten describe bedform undulations or undulating landscapes caused by sedimentation, deformation, or erosion. Examples include ripple-like features on sandstones or undulating strata due to tectonic movement.

In electrical engineering, Welligkeit refers to ripple in a voltage or current, arising from incomplete smoothing of rectified signals or from periodic disturbances. Ripple is quantified by its amplitude and frequency and mitigated by filters or regulators.

Beyond these, the term can denote any wave-like pattern in surfaces, materials, or data, including textile or aesthetic contexts.