this is for holding javascript data
Matteo Cantiello edited Convective Velocities.tex
over 9 years ago
Commit id: 638bb6e02d9109b0977bec0b290092f3b284fe3c
deletions | additions
diff --git a/Convective Velocities.tex b/Convective Velocities.tex
index eebc8e2..9e78e64 100644
--- a/Convective Velocities.tex
+++ b/Convective Velocities.tex
...
\end{equation}
An average of $W(\Delta r)$ over all possible values of $\Delta r$ and a choice of a numerical factor (1/4) in exchanging $\Delta r$ with $\lambda$ leads to the following expression ($W$ depends quadratically on $\Delta r$):
\begin{equation}
\bar{W} \overline{W} (\lambda) = \frac{1}{4} W(\lambda) = - \frac{1}{8} g \Delta \rho (\lambda) \lambda.
\end{equation}
Under the assumption of no dissipative forces, no transfer of kinetic energy to surrounding matter and no heat loss, then one would conclude $\bar{W}(\lambda) = \bar{1/2\rho v^2}$. However in the MLT one assumes that only half of this work is transformed into kinetic energy. This leads to
\begin{equation}
\overline{\frac{1}{2}\rho v^2} \simeq \frac{1}{2}\rho \bar{v}^2 =
\frac{1}{2}\bar{W} \frac{1}{2}\overline{W} (\lambda) = - \frac{1}{16} g \Delta \rho (\lambda) \lambda,
\end{equation}
so that the velocity of convective elements at the level where the mixing length is $\lambda$ can be expressed as
\begin{equation}