[time-nuts] NPR story on coupled pendulums

[Bill Beam]

Yes.  The Q is increased.  And for a pair operating out of phase (the desired mode),
external common mode disturbances are mitigated.

On Thu, 30 Jul 2015 10:14:45 -0700, Eric Garner wrote:

>Is there any stability benefit to having a bunch of "coupled" pendulum
>clocks?

>On Wed, Jul 29, 2015 at 4:22 PM, Bill Beam <wbeam at gci.net> wrote:

>> These University Of Lisbon "Scientists" have rediscovered a very old wheel.
>>
>> Old physics:  Two coupled nearly identical harmonic oscillators have two
>> stable states.
>> They will operate with relative phase = zero or 180deg. How they are
>> coupled is not
>> an issue; they only need to be able to transfer energy one to the other.
>>
>> Regards
>>
>> On Wed, 29 Jul 2015 13:44:19 -0500, Bill Hawkins wrote:
>>
>> >They talk about sound pulses affecting the pendulums.
>>
>> >Sounds more likely that the mechanical vibration transmitted through the
>> >aluminum bar affects the escapements.
>>
>> >Perhaps the 'tock' side generates the strongest pulse, and the 'tick'
>> >side is sensitive enough to be affected by that pulse.
>>
>> >That would soon have the clocks synchronized out of phase, provided the
>> >mounting arrangement did not absorb too much of the pulse energy.
>>
>> >The situation is similar to synchronizing a TV vertical oscillator
>> >(running a bit slow) with the received sync pulse from the broadcast
>> >station, no?
>>
>> >Bill Hawkins
>>
>>
>> >-----Original Message-----
>> >From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Hal
>> >Murray
>> >Sent: Tuesday, July 28, 2015 10:55 PM
>> >To: time-nuts at febo.com
>> >Cc: Hal Murray
>> >Subject: [time-nuts] NPR story on coupled pendulums
>>
>> >University Of Lisbon Scientists Solve Pendulum Clock Mystery
>>
>> >Two professors at the University of Lisbon say they have discovered why
>> >the pendulums of clocks set on the same surface will eventually swing
>> >together in opposing directions.
>>
>> >http://www.npr.org/2015/07/28/427178282/university-of-lisbon-scientists-
>> >solve-
>> >pendulum-clock-mystery
>>
>> >I thought the NPR story was not very interesting.  (But it probably
>> >wasn't targeted at time-nuts. :)
>>
>> >----------
>>
>> >Here is the paper:
>> >  Huygens synchronization of two clocks
>> >  http://www.nature.com/srep/2015/150723/srep11548/full/srep11548.html
>>
>>
>> >--
>> >These are my opinions.  I hate spam.
>>
>>
>>
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>>
>>
>> Bill Beam
>> NL7F
>>
>>
>>
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>-- 
>--Eric
>_________________________________________
>Eric Garner
>_______________________________________________
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Bill Beam
NL7F