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authorPrefetch2022-10-20 18:25:31 +0200
committerPrefetch2022-10-20 18:25:31 +0200
commit16555851b6514a736c5c9d8e73de7da7fc9b6288 (patch)
tree76b8bfd30f8941d0d85365990bcdbc5d0643cabc /source/know/concept/capillary-action
parente5b9bce79b68a68ddd2e51daa16d2fea73b84fdb (diff)
Migrate from 'jekyll-katex' to 'kramdown-math-sskatex'
Diffstat (limited to 'source/know/concept/capillary-action')
-rw-r--r--source/know/concept/capillary-action/index.md42
1 files changed, 21 insertions, 21 deletions
diff --git a/source/know/concept/capillary-action/index.md b/source/know/concept/capillary-action/index.md
index 1ee3cd4..4b9e76c 100644
--- a/source/know/concept/capillary-action/index.md
+++ b/source/know/concept/capillary-action/index.md
@@ -16,7 +16,7 @@ It occurs when the [Laplace pressure](/know/concept/young-laplace-law/)
from surface tension is much larger in magnitude than the
[hydrostatic pressure](/know/concept/hydrostatic-pressure/) from gravity.
-Consider a spherical droplet of liquid with radius $R$.
+Consider a spherical droplet of liquid with radius $$R$$.
The hydrostatic pressure difference
between the top and bottom of the drop
is much smaller than the Laplace pressure:
@@ -25,17 +25,17 @@ $$\begin{aligned}
2 R \rho g \ll 2 \frac{\alpha}{R}
\end{aligned}$$
-Where $\rho$ is the density of the liquid,
-$g$ is the acceleration due to gravity,
-and $\alpha$ is the energy cost per unit surface area.
+Where $$\rho$$ is the density of the liquid,
+$$g$$ is the acceleration due to gravity,
+and $$\alpha$$ is the energy cost per unit surface area.
Rearranging the inequality yields:
$$\begin{aligned}
R^2 \ll \frac{\alpha}{\rho g}
\end{aligned}$$
-From the right-hand side we define the **capillary length** $L_c$,
-so gravity is negligible if $R \ll L_c$:
+From the right-hand side we define the **capillary length** $$L_c$$,
+so gravity is negligible if $$R \ll L_c$$:
$$\begin{aligned}
\boxed{
@@ -44,10 +44,10 @@ $$\begin{aligned}
}
\end{aligned}$$
-In general, for a system with characteristic length $L$,
+In general, for a system with characteristic length $$L$$,
the relative strength of gravity compared to surface tension
-is described by the **Bond number** $\mathrm{Bo}$
-or **Eötvös number** $\mathrm{Eo}$:
+is described by the **Bond number** $$\mathrm{Bo}$$
+or **Eötvös number** $$\mathrm{Eo}$$:
$$\begin{aligned}
\boxed{
@@ -58,16 +58,16 @@ $$\begin{aligned}
}
\end{aligned}$$
-The right-most side gives an alternative way of understanding $\mathrm{Bo}$:
-$m$ is the mass of a cube with side $L$, such that the numerator is the weight force,
+The right-most side gives an alternative way of understanding $$\mathrm{Bo}$$:
+$$m$$ is the mass of a cube with side $$L$$, such that the numerator is the weight force,
and the denominator is the tension force of the surface.
-In any case, capillary action can be observed when $\mathrm{Bo \ll 1}$.
+In any case, capillary action can be observed when $$\mathrm{Bo \ll 1}$$.
The most famous example of capillary action is **capillary rise**,
-where a liquid "climbs" upwards in a narrow vertical tube with radius $R$,
+where a liquid "climbs" upwards in a narrow vertical tube with radius $$R$$,
apparently defying gravity.
Assuming the liquid-air interface is a spherical cap
-with constant [curvature](/know/concept/curvature/) radius $R_c$,
+with constant [curvature](/know/concept/curvature/) radius $$R_c$$,
then we know that the liquid is at rest
when the hydrostatic pressure equals the Laplace pressure:
@@ -77,12 +77,12 @@ $$\begin{aligned}
= 2 \alpha \frac{\cos\theta}{R}
\end{aligned}$$
-Where $\theta$ is the liquid-tube contact angle,
-and we are neglecting variations of the height $h$ due to the curvature
+Where $$\theta$$ is the liquid-tube contact angle,
+and we are neglecting variations of the height $$h$$ due to the curvature
(i.e. the [meniscus](/know/concept/meniscus/)).
-By isolating the above equation for $h$,
+By isolating the above equation for $$h$$,
we arrive at **Jurin's law**,
-which predicts the height climbed by a liquid in a tube with radius $R$:
+which predicts the height climbed by a liquid in a tube with radius $$R$$:
$$\begin{aligned}
\boxed{
@@ -91,7 +91,7 @@ $$\begin{aligned}
}
\end{aligned}$$
-Depending on $\theta$, $h$ can be negative,
+Depending on $$\theta$$, $$h$$ can be negative,
i.e. the liquid might descend below the ambient level.
@@ -106,7 +106,7 @@ $$\begin{aligned}
\approx 2 \pi R (\alpha_{sg} - \alpha_{sl})
\end{aligned}$$
-Where $\alpha_{sg}$ and $\alpha_{sl}$ are the energy costs
+Where $$\alpha_{sg}$$ and $$\alpha_{sl}$$ are the energy costs
of the solid-gas and solid-liquid interfaces.
Thanks to the [Young-Dupré relation](/know/concept/young-dupre-relation/),
we can rewrite this as follows:
@@ -116,7 +116,7 @@ $$\begin{aligned}
= 2 \alpha \cos\theta
\end{aligned}$$
-Isolating this for $h$ simply yields Jurin's law again, as expected.
+Isolating this for $$h$$ simply yields Jurin's law again, as expected.