/[MITgcm]/manual/s_examples/rotating_tank/tank.tex
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1 afe 1.10 % $Header: /u/gcmpack/manual/part3/case_studies/rotating_tank/tank.tex,v 1.9 2004/07/27 13:40:09 afe 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     \label{sect:eg-tank}
18 afe 1.2 \label{www:tutorials}
19    
20 afe 1.4 This section illustrates an example of MITgcm simulating a laboratory
21 afe 1.10 experiment on much smaller scales than those commonly considered in
22     geophysical
23 afe 1.4 fluid dynamics.
24    
25     \subsection{Overview}
26     \label{www:tutorials}
27    
28    
29 afe 1.10 This example configuration demonstrates using the MITgcm to simulate
30     a laboratory demonstration using a rotating tank of water with an ice
31 afe 1.4 bucket in the center. The simulation is configured for a laboratory
32     scale on a
33     $3^{\circ}$ $\times$ 20cm
34     cyclindrical grid with twenty-nine vertical
35     levels.
36     \\
37 afe 1.10 example illustration from GFD lab here
38     \\
39 afe 1.4
40    
41 afe 1.2
42 afe 1.3
43    
44     \subsection{Equations Solved}
45     \label{www:tutorials}
46 afe 1.1
47 afe 1.3
48     \subsection{Discrete Numerical Configuration}
49     \label{www:tutorials}
50    
51     The domain is discretised with
52 afe 1.10 a uniform cylindrical grid spacing in the horizontal set to
53     $\Delta a=1$~cm and $\Delta \phi=3^{\circ}$, so
54     that there are 120 grid cells in the azimuthal direction and thirty-one grid cells in the radial. Vertically the
55     model is configured with twenty-nine layers of uniform 0.5cm thickness.
56     \\
57     something about heat flux
58 afe 1.2
59 afe 1.3 \subsection{Code Configuration}
60 afe 1.1 \label{www:tutorials}
61 afe 1.3 \label{SEC:eg-baro-code_config}
62 afe 1.1
63 afe 1.5 The model configuration for this experiment resides under the
64     directory {\it verification/rotatingi\_tank/}. The experiment files
65 afe 1.1 \begin{itemize}
66     \item {\it input/data}
67     \item {\it input/data.pkg}
68     \item {\it input/eedata},
69 afe 1.5 \item {\it input/bathyPol.bin},
70     \item {\it input/thetaPol.bin},
71 afe 1.1 \item {\it code/CPP\_EEOPTIONS.h}
72     \item {\it code/CPP\_OPTIONS.h},
73 afe 1.5 \item {\it code/SIZE.h}.
74 afe 1.1 \end{itemize}
75 afe 1.5
76 afe 1.3 contain the code customizations and parameter settings for this
77 afe 1.1 experiments. Below we describe the customizations
78     to these files associated with this experiment.
79    
80     \subsubsection{File {\it input/data}}
81     \label{www:tutorials}
82    
83     This file, reproduced completely below, specifies the main parameters
84     for the experiment. The parameters that are significant for this configuration
85     are
86    
87     \begin{itemize}
88    
89 afe 1.10 \item Line 10, \begin{verbatim} viscAh=5.0E-6, \end{verbatim} this line sets
90     the Laplacian friction coefficient to $6 \times 10^{-6} m^2s^{-1}$,
91     which is ususally
92 afe 1.6 low because of the small scale, presumably.... qqq
93    
94 afe 1.10 \item Line 19, \begin{verbatim}f0=0.5 , \end{verbatim} this line sets the
95     coriolis term, and represents a tank spinning at 2/s
96     \item Line 20, \begin{verbatim} beta=1.E-11, \end{verbatim} this line sets
97 afe 1.3 $\beta$ (the gradient of the coriolis parameter, $f$) to $10^{-11} s^{-1}m^{-1}$
98    
99 afe 1.10 \item Lines 27 and 28
100 afe 1.3 \begin{verbatim}
101 afe 1.6 rigidLid=.TRUE.,
102     implicitFreeSurface=.FALSE.,
103 afe 1.3 \end{verbatim}
104 afe 1.6
105 afe 1.10 qqq these lines do the opposite of the following:
106 afe 1.6 suppress the rigid lid formulation of the surface
107 afe 1.3 pressure inverter and activate the implicit free surface form
108     of the pressure inverter.
109 afe 1.1
110 afe 1.10 \item Line 44,
111 afe 1.1 \begin{verbatim}
112 afe 1.10 nIter=0,
113 afe 1.1 \end{verbatim}
114 afe 1.3 this line indicates that the experiment should start from $t=0$
115     and implicitly suppresses searching for checkpoint files associated
116     with restarting an numerical integration from a previously saved state.
117 afe 1.2
118 afe 1.10 \item Line 47,
119 afe 1.1 \begin{verbatim}
120 afe 1.6 deltaT=0.1,
121 afe 1.1 \end{verbatim}
122 afe 1.6 This line sets the integration timestep to $0.1s$. This is an unsually
123     small value among the examples due to the small physical scale of the
124     experiment.
125 afe 1.1
126 afe 1.10 \item Line 58,
127 afe 1.1 \begin{verbatim}
128 afe 1.6 usingCylindricalGrid=.TRUE.,
129 afe 1.1 \end{verbatim}
130 afe 1.3 This line requests that the simulation be performed in a
131 afe 1.7 cylindrical coordinate system.
132 afe 1.1
133 afe 1.10 \item Line 60,
134 afe 1.1 \begin{verbatim}
135 afe 1.7 dXspacing=3,
136 afe 1.1 \end{verbatim}
137 afe 1.10 This line sets the azimuthal grid spacing between each $x$-coordinate line
138 afe 1.3 in the discrete grid. The syntax indicates that the discrete grid
139 afe 1.7 should be comprise of $120$ grid lines each separated by $3^{\circ}$.
140    
141    
142 afe 1.1
143 afe 1.10 \item Line 61,
144 afe 1.1 \begin{verbatim}
145 afe 1.7 dYspacing=0.01,
146 afe 1.1 \end{verbatim}
147 afe 1.10 This line sets the radial cylindrical grid spacing between each $a$-coordinate line
148 afe 1.7 in the discrete grid to $1cm$.
149 afe 1.1
150 afe 1.10 \item Line 62,
151 afe 1.1 \begin{verbatim}
152 afe 1.7 delZ=29*0.005,
153 afe 1.2 \end{verbatim}
154 afe 1.3 This line sets the vertical grid spacing between each z-coordinate line
155     in the discrete grid to $5000m$ ($5$~km).
156 afe 1.1
157 afe 1.10 \item Line 68,
158 afe 1.1 \begin{verbatim}
159 afe 1.7 bathyFile='bathyPol.bin',
160 afe 1.1 \end{verbatim}
161     This line specifies the name of the file from which the domain
162 afe 1.7 ``bathymetry'' (tank depth) is read. This file is a two-dimensional
163 afe 1.10 ($a,\phi$) map of
164 afe 1.1 depths. This file is assumed to contain 64-bit binary numbers
165 afe 1.10 giving the depth of the model at each grid cell, ordered with the $\phi$
166 afe 1.1 coordinate varying fastest. The points are ordered from low coordinate
167 afe 1.7 to high coordinate for both axes. The units and orientation of the
168 afe 1.1 depths in this file are the same as used in the MITgcm code. In this
169 afe 1.7 experiment, a depth of $0m$ indicates an area outside of the tank
170     and a depth
171     f $-0.145m$ indicates the tank itself.
172 afe 1.1
173 afe 1.10 \item Line 67,
174 afe 1.7 \begin{verbatim}
175     hydrogThetaFile='thetaPol.bin',
176     \end{verbatim}
177     This line specifies the name of the file from which the initial values
178 afe 1.10 of temperature
179 afe 1.7 are read. This file is a three-dimensional
180     ($x,y,z$) map and is enumerated and formatted in the same manner as the
181     bathymetry file.
182 afe 1.1
183 afe 1.7 \item Line qqq
184 afe 1.1 \begin{verbatim}
185 afe 1.7 tCyl = 0
186 afe 1.1 \end{verbatim}
187 afe 1.7 This line specifies the temperature in degrees Celsius of the interior
188     wall of the tank -- usually a bucket of ice water.
189    
190 afe 1.1
191     \end{itemize}
192    
193     \noindent other lines in the file {\it input/data} are standard values
194     that are described in the MITgcm Getting Started and MITgcm Parameters
195     notes.
196    
197 afe 1.2 \begin{small}
198 afe 1.5 \input{part3/case_studies/rotating_tank/input/data}
199 afe 1.2 \end{small}
200 afe 1.1
201     \subsubsection{File {\it input/data.pkg}}
202     \label{www:tutorials}
203    
204     This file uses standard default values and does not contain
205 afe 1.3 customizations for this experiment.
206 afe 1.1
207     \subsubsection{File {\it input/eedata}}
208     \label{www:tutorials}
209    
210     This file uses standard default values and does not contain
211 afe 1.3 customizations for this experiment.
212 afe 1.1
213 afe 1.6 \subsubsection{File {\it input/thetaPol.bin}}
214 afe 1.1 \label{www:tutorials}
215    
216 afe 1.6 The {\it input/thetaPol.bin} file specifies a three-dimensional ($x,y,z$)
217 afe 1.10 map of initial values of $\theta$ in degrees Celsius. This particular
218     experiment is set to random values x around 20C to provide initial
219     perturbations.
220 afe 1.1
221 afe 1.6 \subsubsection{File {\it input/bathyPol.bin}}
222 afe 1.1 \label{www:tutorials}
223    
224    
225 afe 1.6 The {\it input/bathyPol.bin} file specifies a two-dimensional ($x,y$)
226 afe 1.1 map of depth values. For this experiment values are either
227 afe 1.6 $0m$ or {\bf -delZ}m, corresponding respectively to outside or inside of
228     the tank. The file contains a raw binary stream of data that is enumerated
229 afe 1.1 in the same way as standard MITgcm two-dimensional, horizontal arrays.
230    
231     \subsubsection{File {\it code/SIZE.h}}
232     \label{www:tutorials}
233    
234     Two lines are customized in this file for the current experiment
235    
236     \begin{itemize}
237    
238     \item Line 39,
239 afe 1.7 \begin{verbatim} sNx=120, \end{verbatim} this line sets
240 afe 1.1 the lateral domain extent in grid points for the
241     axis aligned with the x-coordinate.
242    
243     \item Line 40,
244 afe 1.7 \begin{verbatim} sNy=31, \end{verbatim} this line sets
245 afe 1.1 the lateral domain extent in grid points for the
246     axis aligned with the y-coordinate.
247    
248     \end{itemize}
249    
250     \begin{small}
251 afe 1.7 \input{part3/case_studies/rotating_tank/code/SIZE.h}
252 afe 1.1 \end{small}
253    
254     \subsubsection{File {\it code/CPP\_OPTIONS.h}}
255     \label{www:tutorials}
256    
257     This file uses standard default values and does not contain
258 afe 1.3 customizations for this experiment.
259 afe 1.1
260    
261     \subsubsection{File {\it code/CPP\_EEOPTIONS.h}}
262     \label{www:tutorials}
263    
264     This file uses standard default values and does not contain
265 afe 1.3 customizations for this experiment.
266 afe 1.2

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