Maximum Droplet Volume on Horizontal Cylindrical Surfaces

The maximum volume (Ω) of a droplet that can remain attached to a horizontal fiber defines the stability limit of droplet-fiber interactions, phenomena common in nature and critical to diverse engineering applications. Existing predictive models for Ω show limitations in accurately capturing the dependence of Ω on the fiber size and wettability. To address this gap, we systematically investigated Ω on a horizontal fiber through numerical simulations and experiments. A comprehensive semi-empirical model for Ω is developed and validated against both experimental measurements and reference simulations. This model establishes a new scaling under which the normalized maximum droplet volume depends solely on the contact angle and remains valid across a wide spectrum from a submillimeter-thin fiber to the flat-surface limit, regardless of the diverse morphologies that droplets exhibit.