[kdang]

Hello,

Could I get suggestions on how to model the following scenario?

I've been trying to build a model to simulate the impact of rain droplets on surfaces with different water contact angles (WCAs).

The goal is to capture the droplet shape after impact on 1) a hydrophobic surface with WCA of 120 degrees and 2) a hydrophilic surface with WCA of 5 degrees.

Then, I would extract the droplet shapes from Fluent and import them into Speos (an optical simulation software) to study how different water droplet shapes interact with light.

During the first trial, I used VOF method. The droplets started on the surfaces with zero velocity and then slid down due to gravity. There was a clear difference in droplet shapes due to the difference in WCA of the surfaces.

Then, I continued to use the VOF method for a second trial. This time, I moved the droplets away from the surfaces and added vertical and horizontal velocities to the droplets. However, I could detect any difference in droplet shapes as they impacted and slid down the surfaces.

I also refined the mesh near the surfaces, but it did not help.

I also thought about using the Lagrangian Wall Film and a Reflect boundary condition for the surfaces. But I don't have data for the coefficient of restitution. WCA is the only data that I have.

Has anyone done this kind of simulations in the past?

I greatly appreciate any suggestions on how to do this kind of simulations successfully.

Best regards,
Khanh