User Tools

Site Tools


equations:continuity_equation

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
equations:continuity_equation [2018/04/19 10:07]
jakobadmin [Concrete]
equations:continuity_equation [2020/03/03 10:38] (current)
128.179.254.165
Line 1: Line 1:
-<WRAP lag> $\color{blue}{\frac{\partial \rho}{\partial t}}  ​\color{magenta}{\rho \vec \nabla ​ \vec v} = \color{red}{\sigma} $</​WRAP>​+<WRAP lag> $\color{blue}{\frac{\partial \rho}{\partial t}}  ​= \color{red}{\sigma} - \color{magenta}{\rho \vec{\nabla} \cdot \vec{v}} $</​WRAP>​
  
 ====== Continuity Equation ====== ====== Continuity Equation ======
Line 5: Line 5:
 <tabbox Intuitive> ​ <tabbox Intuitive> ​
  
-The continuity equation states that the $\color{red}{\text{total amount of a quantity (like water) that is produced (or destroyed) inside some volume}}$ is proportional to the $\color{blue}{\text{change of the quantity}}$ plus the $\color{magenta}{\text{total amount that flows in minus the amount that flows out of the volume}}$.  +The continuity equation states that the total $\color{blue}{\text{change of some quantity}}$ is equal to the $\color{red}{\text{amount that gets produced}}$ ​minus the amount that $\color{magenta}{\text{flows out of the volume}}$.
- +
-Or formulated differently, ​the total $\color{blue}{\text{change of some quantity}}$ is equal to the $\color{red}{\text{amount that gets produced}}$ ​plus the amount that $\color{magenta}{\text{flows in minus the amount that flows out of the volume}}$.+
  
 [{{ :​equations:​venturi.gif?​nolink |Image by Thierry Dugnolle}}] [{{ :​equations:​venturi.gif?​nolink |Image by Thierry Dugnolle}}]
Line 41: Line 39:
 $$ \nabla \cdot  J  + \frac { \partial ( \nabla \cdot  D  ) } { \partial t } = 0. $$ \nabla \cdot  J  + \frac { \partial ( \nabla \cdot  D  ) } { \partial t } = 0.
 $$ $$
-Finally, we use another [[equations:​maxwell_equations|Maxwell equation]], namely [[equations:​yang_mills_equations:​gauss_law|Gauss law]], ​+Finally, we use another [[equations:​maxwell_equations|Maxwell equation]], namely [[formulas:​gauss_law|Gauss law]], ​
 $$\nabla \cdot  D  = \rho $$\nabla \cdot  D  = \rho
  $$  $$
equations/continuity_equation.1524125271.txt.gz · Last modified: 2018/04/19 08:07 (external edit)