Pipe Length Required to Change 2Ø Flow Regimes?

[KernOily]

Hi guys. Has anyone seen any rules of thumb for the length of pipe required to change a two-phase flow regime from, say, annular to stratified? My simulator only tells me what the regime is at any point along the line and can't do the transition. The correlations don't really handle the transitions anyway as far as I know. I could probably fudge it and run the simulation at every half-foot along the line while gradually incrementing up the pipe ID but that's the last resort.

I'm looking for something like '20 diameters required to change from wavy to stratified' etc.

Thanks guys!
Pete