Timeline for What is the velocity in the Navier-Stokes equation?
Current License: CC BY-SA 3.0
10 events
| when toggle format | what | by | license | comment | |
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| Jun 21, 2016 at 4:40 | vote | accept | Quantum spaghettification | ||
| Jun 20, 2016 at 22:19 | comment | added | honeste_vivere | An ensemble average requires a quantity that you specify over which one averages. For example, one can do a spatial (yes over space) or temporal (i.e., similar to but not the same as a time-average) ensemble average. There are also energy ensemble averages (e.g., related to the partition function in statistical mechanics). | |
| Jun 20, 2016 at 21:24 | answer | added | valerio | timeline score: 2 | |
| Jun 20, 2016 at 20:52 | history | edited | Qmechanic♦ |
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| Jun 20, 2016 at 19:07 | answer | added | user65081 | timeline score: 2 | |
| Jun 20, 2016 at 18:48 | comment | added | Quantum spaghettification | @honeste_vivere Sorry, please can you specify what you mean by 'ensemble spatial averages'. I know what an ensemble average is, but what do you mean by 'spatial', what are we averaging and over what (space?)? | |
| Jun 20, 2016 at 18:36 | comment | added | honeste_vivere | Kind of but not really... You treat it as an ensemble of fluid elements, not individual particles (which would be kinetic theory). The Navier-Stokes equation is a fluid approximation derived from kinetic theory by taking ensemble spatial averages. It's the bulk flow velocity you find after you "fluidize" the equations, if you will. Does that help? | |
| Jun 20, 2016 at 18:33 | comment | added | Quantum spaghettification | @honeste_vivere would this not be the same as my third option? | |
| Jun 20, 2016 at 18:31 | comment | added | honeste_vivere | The $\mathbf{v}$ is the bulk flow velocity of a fluid element (i.e., a "blob" of the given fluid). | |
| Jun 20, 2016 at 18:28 | history | asked | Quantum spaghettification | CC BY-SA 3.0 |