Influence of Aerodynamic Forces and Mechanical Vibrations on the Motion Behaviour of Droplets, with Particular Emphasis on Automotive Applications
Conf’luence Uwe Janoske
National Research Council of Italy (CNR)
Vendredi 17 avril à 10h30 • Amphithéâtre Nougaro
Droplets occur in many areas of a vehicle. Condensation‑induced droplet formation in exhaust systems can lead to thermal shock, corrosion, and related damage in sensors and electronic components. Droplet‑induced contamination of components, such as camera systems and mirrors, can result in functional impairments. In addition, the efficient separation and transport of oil and water droplets in filtration systems are of signifcant importance. For the design of such systems, a thorough understanding of droplet motion behaviour is essential.
In addition to desired droplet motion, for example during the removal of droplets from camera systems, droplets must be prevented from accumulating at undesirable locations, such as electronic components and sensors. In all of the aforementioned examples, droplets are exposed both to aerodynamic forces and to vibrational excitation induced by mechanical vibrations as well as flow‑induced oscillations.
Within the scope of this presentation, the effects of these superimposed forces on droplet motion are investigated using both numerical simulations and experimental approaches. It is shown that, depending on the frequency range, the superposition of both forces leads to pronounced differences in droplet dynamics, which can potentially be exploited beneficially in system design.
For the numerical modelling of droplet dynamics, grid‑based finite‑volume methods employing the Volume‑of‑Fluid (VoF) approach are used and extended by models accounting for contact angle hysteresis. Furthermore, a particle‑based Smoothed Particle Hydrodynamics (SPH) model for simulating droplet motion, combined with Physics‑Informed Neural Networks (PINNs) for the determination of flow fields, is presented. The various numerical methods, as well as their experimental validation using a range of laser‑optical measurement techniques (LDA, PIV, 3D particle tracking, and shadowgraphy), are demonstrated for different geometries.