[hospital0968]

Greetings!

I am simulating a droplet falling down in air, which is a 2 phase flow problem. I chose VOF; explicit; geo-reconstruction; with droplet size 3 mm diameter and grid size 0.05 mm (which indicates that the interface between liquid and air will be placed exactly on a mesh line).

However, after initializing and patching, I got the contour of VOF water as the fig.


The interface occupies two grid spaces, instead of a single straight line. Furthermore, reducing the grid size also gives me the same result. I understand this is a blurring method for stability concerns while calculating. Unfortunately, I can't find a clear algorithm about how fluent generate this blurring interface.
Can anyone here shed some light on the formulas fluent use to create the blurred interface?
and,
Is there any methods in fluent to compress this blurring interface?

Here are some results of the simulation while the droplet impacts the ground:
1. 1 order momentum:

2. 2 order momentum:


Finally, thanks in advance!