2021/11/05 by Sarah Cleve, Christian Diddens, Cleve, Sarah +7
Engineering · #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Fluid Dynamics and Mixing #Microfluidic and Bio-sensing Technologies #Ultrasound and Hyperthermia Applications
paper · pdf · doi:10.48550/arxiv.2111.03542
openalex publication_date 2021/11/05 · openalex created_date 2022/05/05 · openalex updated_date 2026/07/28
Flow-focusing devices have gained great interest in the past decade, due to\ntheir capability to produce monodisperse microbubbles for diagnostic and\ntherapeutic medical ultrasound applications. However, up-scaling production to\nindustrial scale requires a paradigm shift from single chip operation to highly\nparallelized systems. Parallelization gives rise to fluidic interactions\nbetween nozzles that, in turn, may lead to a decreased monodispersity. Here, we\nstudy the velocity and pressure field fluctuations in a single flow-focusing\nnozzle during bubble production. We experimentally quantify the velocity field\ninside the nozzle at 100 ns time resolution, and a numerical model provides\ninsight into both the oscillatory velocity and pressure fields. Our results\ndemonstrate that, at the length scale of the flow focusing channel, the\nvelocity oscillations propagate at fluid dynamical time scale (order of\nmicroseconds) whereas the dominant pressure oscillations are linked to the\nbubble pinch-off and propagate at a much faster time scale (order of\nnanoseconds).\n