Biomedical subjects

A Wierschem

Publications and source records attributed to A Wierschem.

3 recordsLinked to original sources

PubMed2001

Properties of surface wave trains excited by mass transfer through a liquid surface.

In annular containers, various traveling periodic surface wave trains are generated in liquid layers during the absorption process of a miscible surface-active substance out of the vapor phase. Single and counter-rotating wave trains are observed. We here report on waves found to be dispersion-free associated to mostly longitudinal, dilational surface-tension-gradient-driven motions. We report on interactions of the wave crests and on modulations that lead to wave-number changes of the wave trains. The wave interactions show behavior typically known for solitons.

Journal Article↗

PubMed2000

Internal waves excited by the marangoni effect

Traveling periodic internal wave trains are generated in liquid layers during the absorption process of a miscible surface-active substance out of the vapor phase. In our nonstationary experimental runs, internal waves are excited by surface waves, which had been previously generated by a surface-tension-gradient-driven instability. The internal wave trains adjust their wave number by an Eckhaus instability. Close to the instability threshold narrow and extended pulses are observed. Furthermore, the wave trains can alter their traveling direction, i.e., one wave train traveling in one direction yields to another train, in general of different wave number, traveling in the opposite direction.

Journal Article↗

PubMed1999

Interfacial Wave Motions Due to Marangoni Instability.

In annular containers, traveling periodic wavetrains are generated in liquid layers due to the surface adsorption and subsequent liquid absorption of a miscible surface-active substance. First, localized nucleation of shock-wave-like disturbances are generated by the Marangoni effect. Then, these disturbances yield to surface-wave trains with three-dimensional features which travel through the annular container or to stationary source-and-sink states. To illustrate these phenomena we provide shadowgraph pictures of the waves, space-time diagrams showing the wave evolution and wave modulation, mean frequency of wavetrains as a function of the wave mode, surface deformation, peak-to-trough wave amplitudes, wave sources and sinks, and the time evolution of the estimated Marangoni number. Copyright 1999 Academic Press.

Journal Article↗