The Ideal Gas in Slow Time

Christopher Essex, Bjarne Andresen*

*Corresponding author af dette arbejde

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Abstract

We continue our exploration of thermodynamics at long observational timescales, "slow time," by including turbulent dynamics leading to a condition of fluctuating local equilibrium. Averaging these fluctuations in wind speed and temperature results in a velocity distribution with heavy tails which, however, are necessarily truncated at some large molecular speed preserving all moments of the velocity distribution including the energy. This leads to an expression for the ideal gas law in slow time which as its core has the superficially familiar term 3/2 Nk theta in addition to a term accounting for the large-scale fluctuations, which is also proportional to the particle number N;theta is a new temperature including thermalization of wind. The traditional temperature T no longer exists. Likewise, the additional energy term necessitates a new quantity that parallels entropy in the sense that it captures hidden degrees of freedom. Like entropy, it captures physical properties manifesting indirectly, but on scales larger than the familiar laboratory scales. We call this quantity epitropy.

OriginalsprogEngelsk
TidsskriftJournal of Non-Equilibrium Thermodynamics
Vol/bind46
Udgave nummer1
Sider (fra-til)35-43
Antal sider9
ISSN0340-0204
DOI
StatusUdgivet - jan. 2021

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