A digital holography set-up for 3D vortex flow dynamics

B Lebon, G Perret, S Coëtmellec, G Godard… - Experiments in …, 2016 - Springer
B Lebon, G Perret, S Coëtmellec, G Godard, G Gréhan, D Lebrun, J Brossard
Experiments in Fluids, 2016Springer
In the present paper, a digital in-line holography (DIH) set-up, with a converging beam, is
used to take three-dimensional (3D) velocity measurements of vortices. The vortices are
formed periodically at the edges of a submerged horizontal plate submitted to regular
waves. They take the form of vortex filaments that extend from side to side of the channel.
They undergo strongly three-dimensional instability mechanisms that remain very
complicated to characterize experimentally. The experiments are performed in a 10× 0.3× …
Abstract
In the present paper, a digital in-line holography (DIH) set-up, with a converging beam, is used to take three-dimensional (3D) velocity measurements of vortices. The vortices are formed periodically at the edges of a submerged horizontal plate submitted to regular waves. They take the form of vortex filaments that extend from side to side of the channel. They undergo strongly three-dimensional instability mechanisms that remain very complicated to characterize experimentally. The experiments are performed in a 10 × 0.3 × 0.3 m3 wave flume. The DIH set-up is performed using a modulated laser diode emitting at the wavelength of 640 nm and a lensless CCD camera. The beam crosses the channel side to side. To reveal the flow dynamics, 30-μm hydrogen bubbles are generated at the edge of the plate to serve as tracers. Their locations are recorded on the holograms multiple times to access the dynamics of the flow. This method leads to an accuracy in the order of 100 μm on the axial location. Those measurements have been validated with stereo-PIV measurements. A very good agreement is found on time-averaged velocity fields between the two techniques.
Springer
以上显示的是最相近的搜索结果。 查看全部搜索结果