Water overflow physics

[Pocster]

Hmmmm

 

So I added a diverter to this rain barrel . I thought we were golden .

Then I added a 2nd . Piss down now both tanks full - but full past the inlets so water coming out over both tanks .

 

I though the diverter outlet on the gutter has to be higher than the inlet on the barrel - which it is .

 

Adding a 2nd barrel upset the physics ?

I was expecting water not to be higher than the inlet on either tank .

 

Too difficult to understand on a wet Sunday !

[Pocster]

[Pocster]

[SteamyTea]

Pipes are too small.

You need to solve the Navier Stokes problem, worth a $1,000,000.

Then you can get yourself a new tapemeaure.

[Pocster]

1 minute ago, SteamyTea said:

Pipes are too small.

You need to solve the Navier Stokes problem, worth a $1,000,000.

Then you can get yourself a new tapemeaure.

It’s the supplied pipes for the diverter .

chat tells me I need a pipe between them at the bottom 🤔

[Pocster]

Chat tells me effectively gutter down is a header of water with gravity and that the pressure back from 2 full tanks isn’t enough to stop them overflowing . So the diverter is crap really - it diverts but keeps diverting . Overflow on tank 2 required !

Edited September 7 by Pocster

[G and J]

Isn’t it as simple as the water level in the butts will settle at the height of the diverter, not where the inlet pipe joins the barrel.   
 

The pipe could enter the barrel at the very bottom and the butt would still fill to the height if the diverter, methinks.

[Pocster]

I don

15 minutes ago, G and J said:

Isn’t it as simple as the water level in the butts will settle at the height of the diverter, not where the inlet pipe joins the barrel.   
 

The pipe could enter the barrel at the very bottom and the butt would still fill to the height if the diverter, methinks.

i dont know . I thought the physics were simple . Think I’ll have a coffee and think about this later 😂

[G and J]

31 minutes ago, Pocster said:

I don

i dont know . I thought the physics were simple . Think I’ll have a coffee and think about this later 😂

Don’t think.  Experiment, observe, then think. 
 

Take a clear tube.  Put some water in it. Try and hold it in a ‘U’ shape so that the water level on one side is higher than the other.  

[Pocster]

46 minutes ago, G and J said:

Don’t think.  Experiment, observe, then think. 

But I did that on the entire build !! 😂

[marshian]

The weir in the diverter should not be higher then the top of the tank being filled

 

ideally it should be ~1 cm below it so when the butts are full so is the weir in the diverter and all rainwater in the down pipe flows to drain and the level in the butts does not reach overflow point

[saveasteading]

The physics are (is?)  indeed straight forward.

From the diverter it is all gravity. All rain sticks to the dp sides and goes through the diverter until it sits full at which stage it overflows within the dp.

Any more rain goes on down the dp.

But if the diverter is above the tank it keeps filling the tank and water comes out of the tank top.

 The tank won't fill above the lower diverter.

With 2 inlets I think they need to be at the same level or it will run from the higher to the lower.

 

A link between tanks  is best low down so that it works ASAP when rain arrives. Yours works only when one tank is full, but that is OK.

[marshian]

39 minutes ago, saveasteading said:

 

A link between tanks  is best low down so that it works ASAP when rain arrives. Yours works only when one tank is full, but that is OK.

I always link at the top when daisy chaining water butts - less risk of water loss due to poor sealing on the link pipe

 

when I was daisy chaining - Mrs Alien instructions was to use from furthest from the source first - of course she ignored that because it was quicker to fill a watering can from the fullest one (she doesn’t like waiting for anything) 

 

I’ve since upgraded the taps from std plastic ones to brass full bore ball valves - this way flow rate is less dependent on volume in the butt (it still is faster on a full one compared to a half full one but much less of a difference)

[saveasteading]

8 minutes ago, marshian said:

quicker to fill a watering can from the fullest one 

Good point. It is a pain waiting, so filling one first (link near the top)  is quite a good idea. Or any compromise.