On 08 September, 2021 - Dirk Hohndel via subsurface wrote: > Simple to reproduce. > > Manually add dive - let's just use the default 15m / 40min > Add a tank - 10.0l, start 200bar end 100bar > > Dive overall has a SAC of 9.9l/min > > Because there is no sensor data, we are creating a constant SAC rate > theoretical gas consumption line (at least I thought we did). > But as you hover over the profile from start to finish, you'll see the SAC > rate increase from 7.9l/min to 10.7l/min > > > > Am I misunderstanding what I'm seeing? > Admittedly, I haven't looked at the code, yet. I just saw this underlying > problem reported on Scubaboard and figured I'd share the simple demonstration > of the issue here
This has bin like this ever since we started to gas computations based on non naive p-v-t calculations. We still extrapolate the sac rate based on the naive formula, and later use those extrapolated values to calculate a real sac, so due to compressibility we think we consume less gas in the beginning and more towards the end. A long time ago I took a stab at fixing this but it turned real messy and I just left it. //Anton -- Anton Lundin +46702-161604 _______________________________________________ subsurface mailing list [email protected] http://lists.subsurface-divelog.org/cgi-bin/mailman/listinfo/subsurface
