76 |
continuity equation over the entire depth of the fluid, |
continuity equation over the entire depth of the fluid, |
77 |
from $R_{min}(x,y)$ up to $R_o(x,y)$ |
from $R_{min}(x,y)$ up to $R_o(x,y)$ |
78 |
(Linear free surface): |
(Linear free surface): |
79 |
\begin{displaymath} |
\begin{eqnarray} |
80 |
\epsilon_{fs} \partial_t \eta = |
\epsilon_{fs} \partial_t \eta = |
81 |
\left. \dot{r} \right|_{r=r_{surf}} + \epsilon_{fw} (P-E) = |
\left. \dot{r} \right|_{r=r_{surf}} + \epsilon_{fw} (P-E) = |
82 |
- {\bf \nabla}_r \cdot \int_{R_{min}}^{R_o} \vec{\bf v} dr |
- {\bf \nabla}_r \cdot \int_{R_{min}}^{R_o} \vec{\bf v} dr |
83 |
+ \epsilon_{fw} (P-E) |
+ \epsilon_{fw} (P-E) |
84 |
\end{displaymath} |
\label{eq-cont-2D} |
85 |
|
\end{eqnarray} |
86 |
|
|
87 |
Where $\epsilon_{fs}$,$\epsilon_{fw}$ are two flags to |
Where $\epsilon_{fs}$,$\epsilon_{fw}$ are two flags to |
88 |
distinguish between a free-surface equation ($\epsilon_{fs}=1$) |
distinguish between a free-surface equation ($\epsilon_{fs}=1$) |
326 |
|
|
327 |
Substituting \ref{eq-rtd-hmom} into \ref{eq-rtd-cont}, assuming |
Substituting \ref{eq-rtd-hmom} into \ref{eq-rtd-cont}, assuming |
328 |
$\epsilon_{nh} = 0$ yields a Helmholtz equation for ${\eta}^{n+1}$: |
$\epsilon_{nh} = 0$ yields a Helmholtz equation for ${\eta}^{n+1}$: |
329 |
$$ |
\begin{eqnarray} |
330 |
\epsilon_{fs} {\eta}^{n+1} - |
\epsilon_{fs} {\eta}^{n+1} - |
331 |
{\bf \nabla}_r \cdot \Delta t^2 (R_o-R_{min}) |
{\bf \nabla}_r \cdot \Delta t^2 (R_o-R_{min}) |
332 |
{\bf \nabla}_r B_o {\eta}^{n+1} |
{\bf \nabla}_r B_o {\eta}^{n+1} |
333 |
= {\eta}^* |
= {\eta}^* |
334 |
\label{solve_2d} |
\label{solve_2d} |
335 |
$$ |
\end{eqnarray} |
336 |
where |
where |
337 |
$$ |
\begin{eqnarray} |
338 |
{\eta}^* = \epsilon_{fs} \: {\eta}^{n} - |
{\eta}^* = \epsilon_{fs} \: {\eta}^{n} - |
339 |
\Delta t {\bf \nabla}_r \cdot \int_{R_{min}}^{R_o} \vec{\bf v}^* dr |
\Delta t {\bf \nabla}_r \cdot \int_{R_{min}}^{R_o} \vec{\bf v}^* dr |
340 |
\: + \: \epsilon_{fw} \Delta_t (P-E)^{n} |
\: + \: \epsilon_{fw} \Delta_t (P-E)^{n} |
341 |
$$ |
\label{solve_2d_rhs} |
342 |
|
\end{eqnarray} |
343 |
|
|
344 |
Once ${\eta}^{n+1}$ has been found substituting into \ref{eq-rtd-hmom} |
Once ${\eta}^{n+1}$ has been found substituting into \ref{eq-rtd-hmom} |
345 |
would yield $\vec{\bf v}^{n+1}$ if the model is hydrostatic |
would yield $\vec{\bf v}^{n+1}$ if the model is hydrostatic |