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A comment on Large-scale ‘sand battery’ goes online in Finland. Parent comment

Re:Large-scale ‘sand battery’ goes online in Finland by samatman on Wednesday July 06, 2022 @07:14PM (#32008059)
Volume to surface area: for every doubling of diameter you have 1/16th the losses, before factoring in insulation.

1/16th probably sounds high, but the extra halving is because flow rate increases as radius^4, not cubed as one might guess.

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Re:Large-scale ‘sand battery’ goes online in Finland by mwint on Wednesday July 06, 2022 @07:39PM (#32008252)
Naively, I would have guessed flow rate to increase as radius^2 (cross sectional area).

Guessing the reason for extra increased flow is some edge effect / turbulence mechanisms?

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Re:Large-scale ‘sand battery’ goes online in Finland by samatman on Wednesday July 06, 2022 @08:35PM (#32008653)
Center flow at a given pressure is also square the radius.
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