Środowiskowe Seminarium Fizyki Atmosfery

Acoustic precipitation enhancement technology uses strong low-frequency sound waves to enhance the relative motion and thus the collisional growth of cloud droplets, leading to increased rainfall. As a forward-looking technology, acoustic precipitation enhancement is viewed to be low-cost, environmentally friendly, simple to operate, and easy to promote. However, the science behind this technology, namely, turbulent cloud microphysics and dynamics under the action of sound waves, is a challenging multi-scale, multi-physics, and interdisciplinary research topic. In this talk, I will first review previous theoretical understanding on the mechanisms of acoustic agglomeration and related collision kernels, and discuss how the magnitude of these collision kernels compared to collision kernels due to gravitational settling motion and turbulent air fluctuations. We then solve the stochastic collection equation under the combined actions of gravity and acoustic waves, to study how acoustic waves affect the collisional growth of cloud droplets. In particular, we study how the growth rate depends on the frequency, the applied duration, and intensity of sound waves. It is found that an optimal wave frequency exists and its value depends on the initial droplet size distribution, applied duration, and wave intensity. We also compare our findings with previous experimental observations and theoretical results. >>> Join Zoom Meeting >>>https://uw-edu-pl.zoom.us/j/94443885713?pwd=MFk1bERoaVhaY2pJQW1hZWdaTlg4Zz09Meeting ID: 944 4388 5713Passcode: 330254