From a39bb3b8aab1aeb4fceaedc54c756703819776c3 Mon Sep 17 00:00:00 2001 From: Prefetch Date: Sat, 17 Dec 2022 18:19:26 +0100 Subject: Rewrite "Lagrange multiplier", various improvements --- source/know/concept/material-derivative/index.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'source/know/concept/material-derivative') diff --git a/source/know/concept/material-derivative/index.md b/source/know/concept/material-derivative/index.md index 93e8ad0..7225053 100644 --- a/source/know/concept/material-derivative/index.md +++ b/source/know/concept/material-derivative/index.md @@ -16,9 +16,9 @@ e.g. the temperature or pressure, represented by a scalar field $$f(\va{r}, t)$$. If the fluid is static, the evolution of $$f$$ is simply $$\ipdv{f}{t}$$, -since each point of the fluid is motionless. +since each point is motionless. However, if the fluid is moving, we have a problem: -the fluid molecules at position $$\va{r} = \va{r}_0$$ are not necessarily +the fluid molecules at position $$\va{r} = \va{r}_0$$ are not the same ones at time $$t = t_0$$ and $$t = t_1$$. Those molecules take $$f$$ with them as they move, so we need to account for this transport somehow. -- cgit v1.2.3