/[MITgcm]/manual/s_examples/rotating_tank/tank.tex
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1 jmc 1.18 % $Header: /u/gcmpack/manual/s_examples/rotating_tank/tank.tex,v 1.17 2010/08/27 13:25:32 jmc Exp $
2 afe 1.1 % $Name: $
3    
4     \bodytext{bgcolor="#FFFFFFFF"}
5    
6     %\begin{center}
7 afe 1.3 %{\Large \bf Using MITgcm to Simulate a Rotating Tank in Cylindrical
8     %Coordinates}
9 afe 1.1 %
10     %\vspace*{4mm}
11     %
12     %\vspace*{3mm}
13 afe 1.3 %{\large May 2001}
14 afe 1.1 %\end{center}
15    
16 afe 1.3 \section{A Rotating Tank in Cylindrical Coordinates}
17 jmc 1.18 \label{sec:eg-tank}
18     %\label{www:tutorials}
19 edhill 1.11 \begin{rawhtml}
20     <!-- CMIREDIR:eg-tank: -->
21     \end{rawhtml}
22 jmc 1.16 \begin{center}
23     (in directory: {\it verification/rotating\_tank/})
24     \end{center}
25 afe 1.2
26 afe 1.4 \subsection{Overview}
27 jmc 1.18 %\label{www:tutorials}
28 afe 1.12
29     This example configuration demonstrates using the MITgcm to simulate a
30     laboratory demonstration using a differentially heated rotating
31     annulus of water. The simulation is configured for a laboratory scale
32 edhill 1.14 on a $3^{\circ}\times1\mathrm{cm}$ cyclindrical grid with twenty-nine
33 afe 1.12 vertical levels of 0.5cm each. This is a typical laboratory setup for
34     illustration principles of GFD, as well as for a laboratory data
35 molod 1.15 assimilation project. The files for this experiment can be found in
36     the verification directory under rotating\_tank.
37 afe 1.4 \\
38 afe 1.12
39 afe 1.10 example illustration from GFD lab here
40     \\
41 afe 1.4
42    
43 afe 1.2
44 afe 1.3
45    
46     \subsection{Equations Solved}
47 jmc 1.18 %\label{www:tutorials}
48 afe 1.1
49 afe 1.3
50     \subsection{Discrete Numerical Configuration}
51 jmc 1.18 %\label{www:tutorials}
52 afe 1.3
53 afe 1.12 The domain is discretised with a uniform cylindrical grid spacing in
54     the horizontal set to $\Delta a=1$~cm and $\Delta \phi=3^{\circ}$, so
55     that there are 120 grid cells in the azimuthal direction and
56     thirty-one grid cells in the radial, representing a tank 62cm in
57     diameter. The bathymetry file sets the depth=0 in the nine lowest
58     radial rows to represent the central of the annulus. Vertically the
59     model is configured with twenty-nine layers of uniform 0.5cm
60     thickness.
61 afe 1.10 \\
62     something about heat flux
63 afe 1.2
64 afe 1.3 \subsection{Code Configuration}
65 jmc 1.18 %\label{www:tutorials}
66     \label{sec:eg-tank-code_config}
67 afe 1.1
68 afe 1.5 The model configuration for this experiment resides under the
69     directory {\it verification/rotatingi\_tank/}. The experiment files
70 afe 1.1 \begin{itemize}
71     \item {\it input/data}
72     \item {\it input/data.pkg}
73     \item {\it input/eedata},
74 afe 1.5 \item {\it input/bathyPol.bin},
75     \item {\it input/thetaPol.bin},
76 afe 1.1 \item {\it code/CPP\_EEOPTIONS.h}
77     \item {\it code/CPP\_OPTIONS.h},
78 afe 1.5 \item {\it code/SIZE.h}.
79 afe 1.1 \end{itemize}
80 afe 1.5
81 afe 1.3 contain the code customizations and parameter settings for this
82 afe 1.1 experiments. Below we describe the customizations
83     to these files associated with this experiment.
84    
85     \subsubsection{File {\it input/data}}
86 jmc 1.18 %\label{www:tutorials}
87 afe 1.1
88     This file, reproduced completely below, specifies the main parameters
89     for the experiment. The parameters that are significant for this configuration
90     are
91    
92     \begin{itemize}
93    
94 afe 1.12 \item Lines 9-10, \begin{verbatim}
95     viscAh=5.0E-6,
96     viscAz=5.0E-6,
97     \end{verbatim}
98    
99    
100     These lines set the Laplacian friction coefficient in the horizontal
101     and vertical, respectively. Note that they are several orders of
102     magnitude smaller than the other examples due to the small scale of
103     this example.
104    
105     \item Lines 13-16, \begin{verbatim}
106     diffKhT=2.5E-6,
107     diffKzT=2.5E-6,
108     diffKhS=1.0E-6,
109     diffKzS=1.0E-6,
110    
111     \end{verbatim}
112    
113    
114     These lines set horizontal and vertical diffusion coefficients for
115     temperature and salinity. Similarly to the friction coefficients, the
116     values are a couple of orders of magnitude less than most
117     configurations.
118    
119 afe 1.3
120 afe 1.12 \item Line 17, \begin{verbatim}f0=0.5 , \end{verbatim} this line sets the
121     coriolis term, and represents a tank spinning at about 2.4 rpm.
122    
123     \item Lines 23 and 24
124 afe 1.3 \begin{verbatim}
125 afe 1.6 rigidLid=.TRUE.,
126     implicitFreeSurface=.FALSE.,
127 afe 1.3 \end{verbatim}
128 afe 1.6
129 afe 1.12 These lines activate the rigid lid formulation of the surface
130     pressure inverter and suppress the implicit free surface form
131 afe 1.3 of the pressure inverter.
132 afe 1.1
133 afe 1.12 \item Line 40,
134 afe 1.1 \begin{verbatim}
135 afe 1.10 nIter=0,
136 afe 1.1 \end{verbatim}
137 afe 1.12 This line indicates that the experiment should start from $t=0$ and
138     implicitly suppresses searching for checkpoint files associated with
139     restarting an numerical integration from a previously saved state.
140     Instead, the file thetaPol.bin will be loaded to initialized the
141     temperature fields as indicated below, and other variables will be
142     initialized to their defaults.
143    
144 afe 1.2
145 afe 1.12 \item Line 43,
146 afe 1.1 \begin{verbatim}
147 afe 1.6 deltaT=0.1,
148 afe 1.1 \end{verbatim}
149 afe 1.12 This line sets the integration timestep to $0.1s$. This is an
150     unsually small value among the examples due to the small physical
151     scale of the experiment. Using the ensemble Kalman filter to produce
152     input fields can necessitate even shorter timesteps.
153 afe 1.1
154 afe 1.12 \item Line 56,
155 afe 1.1 \begin{verbatim}
156 afe 1.6 usingCylindricalGrid=.TRUE.,
157 afe 1.1 \end{verbatim}
158 afe 1.3 This line requests that the simulation be performed in a
159 afe 1.7 cylindrical coordinate system.
160 afe 1.1
161 afe 1.12 \item Line 57,
162 afe 1.1 \begin{verbatim}
163 afe 1.7 dXspacing=3,
164 afe 1.1 \end{verbatim}
165 afe 1.10 This line sets the azimuthal grid spacing between each $x$-coordinate line
166 afe 1.3 in the discrete grid. The syntax indicates that the discrete grid
167 afe 1.12 should be comprised of $120$ grid lines each separated by $3^{\circ}$.
168    
169 afe 1.7
170 afe 1.12 \item Line 58,
171 afe 1.1 \begin{verbatim}
172 afe 1.7 dYspacing=0.01,
173 afe 1.1 \end{verbatim}
174    
175 afe 1.12 This line sets the radial cylindrical grid spacing between each
176     $a$-coordinate line in the discrete grid to $1cm$.
177    
178     \item Line 59,
179 afe 1.1 \begin{verbatim}
180 afe 1.7 delZ=29*0.005,
181 afe 1.2 \end{verbatim}
182 afe 1.1
183 afe 1.12 This line sets the vertical grid spacing between each of 29
184     z-coordinate lines in the discrete grid to $0.005m$ ($5$~mm).
185    
186     \item Line 64,
187 afe 1.1 \begin{verbatim}
188 afe 1.7 bathyFile='bathyPol.bin',
189 afe 1.1 \end{verbatim}
190     This line specifies the name of the file from which the domain
191 afe 1.7 ``bathymetry'' (tank depth) is read. This file is a two-dimensional
192 afe 1.10 ($a,\phi$) map of
193 afe 1.1 depths. This file is assumed to contain 64-bit binary numbers
194 afe 1.10 giving the depth of the model at each grid cell, ordered with the $\phi$
195 afe 1.1 coordinate varying fastest. The points are ordered from low coordinate
196 afe 1.7 to high coordinate for both axes. The units and orientation of the
197 afe 1.1 depths in this file are the same as used in the MITgcm code. In this
198 afe 1.7 experiment, a depth of $0m$ indicates an area outside of the tank
199     and a depth
200     f $-0.145m$ indicates the tank itself.
201 afe 1.1
202 afe 1.12 \item Line 65,
203 afe 1.7 \begin{verbatim}
204     hydrogThetaFile='thetaPol.bin',
205     \end{verbatim}
206     This line specifies the name of the file from which the initial values
207 afe 1.10 of temperature
208 afe 1.7 are read. This file is a three-dimensional
209     ($x,y,z$) map and is enumerated and formatted in the same manner as the
210     bathymetry file.
211 afe 1.1
212 afe 1.13 \item Lines 66 and 67
213 afe 1.1 \begin{verbatim}
214 afe 1.12 tCylIn = 0
215     tCylOut = 20
216 afe 1.1 \end{verbatim}
217 afe 1.12 These line specify the temperatures in degrees Celsius of the interior
218     and exterior walls of the tank -- typically taken to be icewater on
219 afe 1.13 the inside and room temperature on the outside.
220 afe 1.7
221 afe 1.1
222     \end{itemize}
223    
224 afe 1.12 \noindent Other lines in the file {\it input/data} are standard values
225 afe 1.1 that are described in the MITgcm Getting Started and MITgcm Parameters
226     notes.
227    
228 afe 1.2 \begin{small}
229 jmc 1.17 \input{s_examples/rotating_tank/input/data}
230 afe 1.2 \end{small}
231 afe 1.1
232     \subsubsection{File {\it input/data.pkg}}
233 jmc 1.18 %\label{www:tutorials}
234 afe 1.1
235     This file uses standard default values and does not contain
236 afe 1.3 customizations for this experiment.
237 afe 1.1
238     \subsubsection{File {\it input/eedata}}
239 jmc 1.18 %\label{www:tutorials}
240 afe 1.1
241     This file uses standard default values and does not contain
242 afe 1.3 customizations for this experiment.
243 afe 1.1
244 afe 1.6 \subsubsection{File {\it input/thetaPol.bin}}
245 jmc 1.18 %\label{www:tutorials}
246 afe 1.1
247 afe 1.6 The {\it input/thetaPol.bin} file specifies a three-dimensional ($x,y,z$)
248 afe 1.10 map of initial values of $\theta$ in degrees Celsius. This particular
249     experiment is set to random values x around 20C to provide initial
250     perturbations.
251 afe 1.1
252 afe 1.6 \subsubsection{File {\it input/bathyPol.bin}}
253 jmc 1.18 %\label{www:tutorials}
254 afe 1.1
255    
256 afe 1.6 The {\it input/bathyPol.bin} file specifies a two-dimensional ($x,y$)
257 afe 1.1 map of depth values. For this experiment values are either
258 afe 1.6 $0m$ or {\bf -delZ}m, corresponding respectively to outside or inside of
259     the tank. The file contains a raw binary stream of data that is enumerated
260 afe 1.1 in the same way as standard MITgcm two-dimensional, horizontal arrays.
261    
262     \subsubsection{File {\it code/SIZE.h}}
263 jmc 1.18 %\label{www:tutorials}
264 afe 1.1
265     Two lines are customized in this file for the current experiment
266    
267     \begin{itemize}
268    
269     \item Line 39,
270 afe 1.7 \begin{verbatim} sNx=120, \end{verbatim} this line sets
271 afe 1.1 the lateral domain extent in grid points for the
272     axis aligned with the x-coordinate.
273    
274     \item Line 40,
275 afe 1.7 \begin{verbatim} sNy=31, \end{verbatim} this line sets
276 afe 1.1 the lateral domain extent in grid points for the
277     axis aligned with the y-coordinate.
278    
279     \end{itemize}
280    
281     \begin{small}
282 jmc 1.17 \input{s_examples/rotating_tank/code/SIZE.h}
283 afe 1.1 \end{small}
284    
285     \subsubsection{File {\it code/CPP\_OPTIONS.h}}
286 jmc 1.18 %\label{www:tutorials}
287 afe 1.1
288     This file uses standard default values and does not contain
289 afe 1.3 customizations for this experiment.
290 afe 1.1
291    
292     \subsubsection{File {\it code/CPP\_EEOPTIONS.h}}
293 jmc 1.18 %\label{www:tutorials}
294 afe 1.1
295     This file uses standard default values and does not contain
296 afe 1.3 customizations for this experiment.
297 afe 1.2

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