Aerofractures in a Hele-Shaw cell: Explaining poromechanics with acoustic signals and signal localization
| Quand ? |
Le 05/07/2016, de 10:45 à 12:00 |
|---|---|
| Où ? | Centre Blaise Pascal |
| Participants |
Semih Turkaya |
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In this work, analogue models are developed in a linear geometry, with confinement and at low porosity to study the instabilities that occur during fast motion of fluid in dense porous materials: fracturing, fingering, and channeling. We study these complex fluid/solid mechanical systems - in a rectangular Hele-Shaw cell with three closed boundaries and one semi-permeable boundary - using optical imaging using a high speed camera (1000 fps) and high frequency resolution accelerometers sensors. Additionally, we develop physical models rendering for the fluid mechanics in the channels and the propagation of microseismic waves around the fracture. Different sources of the signal (air vibration in the carved area, changes in the effective stress due to fluid-solid interactions) are separately analyzed to understand the mechanical evolution during air injection. Furthermore, to locate the acoustic events generated due to local stress rearrangements we propose a new signal localization method (applicable for thin plates) based on energy amplitude attenuation and inversed source amplitude comparison.