I'm definitely sure the issue is with the UDF somewhere, but I'm unable to quite put a finger on what exactly. Below is a picture of the expected variation in properties as compared to Fluent's native method. The UDF I've written right now is the original implementation of FLUENT's VOF, so I'm expecting an arithmetic weighted average as the green line below. nAnd here is an image of the property I'm obtaining through my UDF.nI'll try maybe storing the property values in a file along with the phase fraction to see if I can get any information on it. But any other suggestions would be great.nn