Related papers: Hydrodynamic Doppler effect in flowing soap films
It is widely thought that in steady, gravity-driven, unobstructed soap-film flows, the velocity increases monotonically downstream. Here we show experimentally that the velocity increases, peaks, drops abruptly, then lessens gradually…
We follow the diffusive motion of colloidal particles in soap films with varying $h/d$, where $h$ is the thickness of the film and $d$ the diameter of the particles. The hydrodynamics of these films are determined by looking at the…
We observe tracer particles diffusing in soap films to measure the two-dimensional (2D) viscous properties of the films. We make soap films with a variety of water-glycerol mixtures and of differing thicknesses. The single-particle…
Vertical soap films drain under the influence of gravity, as indicated by the downward motion of colorful horizontal interference fringes observed on their surfaces. In this study conducted with rectangular soap films, we experimentally…
We present a quasi-two dimensional model of flowing soap films that bears striking similarity to the compressible Navier-Stokes equations. The variation in soap film thickness that is commonly used for flow visualization in experiments is…
We discuss the behaviour of a thin soap film facing a frame element: the pressure in the Plateau border around the frame is lower than the film pressure, and the film thins out over a certain distance lambda(t), due to the formation of a…
The present study aims to investigate the motion of buoyant rings in vertical soap films. Thickness differences and related bi-dimensional densities are considered as the motor leading to bi-dimensional buoyancy. We show how this effect can…
An experimental study of Taylor's hypothesis in a quasi-two-dimensional turbulent soap film is presented. A two probe laser Doppler velocimeter enables a non-intrusive simultaneous measurement of the velocity at spatially separated points.…
In the minutes immediately preceeding the rupture of a soap bubble, distinctive and repeatable patterns can be observed. These quasi-stable transient structures are associated with the instabilities of the complex Marangoni flows on the…
We investigate the motion through a wet tube of transverse soap films, or lamellae, of high surface dilatationnal modulus. Combining local thickness and velocity measurements in the wetting film, we reveal a zone of several centimeters in…
We study the formation of propagating large-scale density waves of mixed polar-nematic symmetry in a colony of self-propelled agents that are bound to move along the planar surface of a thin viscous film. The agents act as an insoluble…
We follow the diffusive motion of colloidal particles of diameter $d$ in soap films of varying thickness $h$ with fluorescence microscopy. Diffusion constants are obtained both from one- and two-particle microrheological measurements of…
Although soap films are prone to evaporate due to their large surface to volume ratio, the effect of evaporation on macroscopic film features has often been disregarded in the literature. In this work, we investigate experimentally the…
The spontaneous spreading of non-volatile liquid droplets on solid substrates poses a classic problem in the context of wetting phenomena. It is well known that the spreading of a macroscopic droplet is in many cases accompanied by a thin…
There are different ways for fluid flow to become turbulent, but usually many instabilities take place before that. Among these instabilities the transition from laminar flow to vortex shedding carries significant practical importance. Here…
We measure the Marangoni elasticity of a flowing soap film to be 22 dyne/cm irrespective of its width, thickness, flow speed, or the bulk soap concentration. We perform this measurement by generating an oblique shock in the soap film and…
Liquid foams exhibit menisci whose lengths range from hundreds of microns in microfoams to several centimeters in macroscopic bubble arrangements. These menisci thin under gravity until reaching a steady thickness profile, where hydrostatic…
Liquid foams are widely used in industry for their high effective viscosity, whose local origin is still unclear. This Letter presents new results on the extension of a suspended soap film, in a configuration mimicking the elementary…
Recently a theoretical scheme explaining the vorticity generation by surface waves in liquids was developed [S. Filatov et al., Phys. Rev. Lett. 116, 054501 (2016)]. Here we study how a thin (monomolecular) film presented at the surface of…
Droplet impact on surfactant-laden thin liquid films is investigated experimentally with emphasis on vortex ring dynamics. Bottom- and side-view imaging reveal that increasing surfactant concentration progressively stabilize vortex rings,…