From the paper.
Ultrasounds accelerate extraction processes due to acoustic cavitation [8], [9]. When acoustic bubbles, also called inertial bubbles, collapse near solid materials, such as coffee grounds, they generate micro-jets with the force to fracture the cell walls of plant tissues, intensifying the extraction of the intracellular content [10].
Seems more involved than just aggressive stirring.
https://www.sciencedirect.com/science/article/pii/S1350417724001330
I played D&D for 10 years before I seriously tried DMing. I’m now a year and a half into a 5e game with 4 other players and it’s been great. It helped that YouTube kept sending me Matt Colville videos https://www.youtube.com/watch?v=e-YZvLUXcR8