So, 'back to basics'..
Here's a 1 m radius wheel, with a 1 kg weight attached.
Both have an MoI of 1 kg-m², for a net system MoI of 2 kg-m².
The GPE is thus 1 kg * G * 2 meters = 19.613 J.
The weight drops from TDC to BDC, ten times, incrementing the starting speed by 1 rad/s each run.
The angular momentum rise is then plotted, along with drop time and KE:
Code: Select all
Start Speed Drop Time AM Gain AM Gain KE Gain
_________
Drop Time
1 rad/s 1.288 s 7.080 L 5.497 L/s 19.613 J
2 rad/s 0.961 s 5.719 L 5.951 L/s 19.613 J
3 rad/s 0.769 s 4.698 L 6.109 L/s 19.613 J
4 rad/s 0.637 s 3.935 L 6.178 L/s 19.613 J
5 rad/s 0.541 s 3.359 L 6.209 L/s 19.613 J
6 rad/s 0.469 s 2.915 L 6.215 L/s 19.613 J
7 rad/s 0.412 s 2.567 L 6.231 L/s 19.613 J
8 rad/s 0.367 s 2.288 L 6.234 L/s 19.613 J
9 rad/s 0.331 s 2.061 L 6.227 L/s 19.613 J
10 rad/s 0.301 s 1.874 L 6.226 L/s 19.613 J
As you can see, each drop converts the full GPE to KE.
The AM gain decreases as a function of rising speed and decreasing drop time, as expected.
However there is one new detail here i hadn't noticed before - if we divide the AM gain per drop, by its drop time, we see that the momentum gain per unit time is actually increasing with speed..(!?)
This must have a simple explanation, though it currently eludes me..
As ever, attaining OU efficiency requires fixing the unit energy cost of momentum invariant of RPM.. so this experiment is just trying to scope out the situation, and maybe get a better handle on the barriers between us and that goal.
Already tho we're seeing this increasing L/t dynamic that i'd never have guessed was there..
Not sure what to try next.. but thinking of maybe adding a vMoI, to increase or decrease the net system MoI by, say, 1 kg-m² over each drop. I could then plot the same data, plus CF-PE (+/- CF workload)..
..again tho, no idea what i'd be looking for, other than better understanding the dynamics and spotting anything else i've missed.
This increasing L/t with speed is a surprise tho, eh? I'd've thought it'd be a constant function of drop time relative to gravity's constant acceleration.. or if anything, decreasing with RPM, just as the momentum yield does.. For now, i've no idea why this is happening..