/[MITgcm]/manual/s_examples/rotating_tank/tank.tex
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1 afe 1.9 % $Header: /u/gcmpack/manual/part3/case_studies/rotating_tank/tank.tex,v 1.8 2004/07/26 21:25:34 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     experiment on much smaller scales than those common to geophysical
22     fluid dynamics.
23    
24     \subsection{Overview}
25     \label{www:tutorials}
26    
27    
28     This example experiment demonstrates using the MITgcm to simulate
29     a laboratory experiment with a rotating tank of water with an ice
30     bucket in the center. The simulation is configured for a laboratory
31     scale on a
32     $3^{\circ}$ $\times$ 20cm
33     cyclindrical grid with twenty-nine vertical
34     levels.
35     \\
36    
37    
38 afe 1.2
39 afe 1.3
40    
41     \subsection{Equations Solved}
42     \label{www:tutorials}
43 afe 1.1
44 afe 1.3
45     \subsection{Discrete Numerical Configuration}
46     \label{www:tutorials}
47    
48     The domain is discretised with
49     a uniform grid spacing in the horizontal set to
50     $\Delta x=\Delta y=20$~km, so
51     that there are sixty grid cells in the $x$ and $y$ directions. Vertically the
52     model is configured with a single layer with depth, $\Delta z$, of $5000$~m.
53    
54 afe 1.2
55 afe 1.3 \subsection{Code Configuration}
56 afe 1.1 \label{www:tutorials}
57 afe 1.3 \label{SEC:eg-baro-code_config}
58 afe 1.1
59 afe 1.5 The model configuration for this experiment resides under the
60     directory {\it verification/rotatingi\_tank/}. The experiment files
61 afe 1.1 \begin{itemize}
62     \item {\it input/data}
63     \item {\it input/data.pkg}
64     \item {\it input/eedata},
65 afe 1.5 \item {\it input/bathyPol.bin},
66     \item {\it input/thetaPol.bin},
67 afe 1.1 \item {\it code/CPP\_EEOPTIONS.h}
68     \item {\it code/CPP\_OPTIONS.h},
69 afe 1.5 \item {\it code/SIZE.h}.
70 afe 1.1 \end{itemize}
71 afe 1.5
72 afe 1.3 contain the code customizations and parameter settings for this
73 afe 1.1 experiments. Below we describe the customizations
74     to these files associated with this experiment.
75    
76     \subsubsection{File {\it input/data}}
77     \label{www:tutorials}
78    
79     This file, reproduced completely below, specifies the main parameters
80     for the experiment. The parameters that are significant for this configuration
81     are
82    
83     \begin{itemize}
84    
85 afe 1.6 \item Line X, \begin{verbatim} viscAh=5.0E-6, \end{verbatim} this line sets
86     the Laplacian friction coefficient to $0.000006 m^2s^{-1}$, which is ususally
87     low because of the small scale, presumably.... qqq
88    
89     \item Line X, \begin{verbatim}f0=0.5 , \end{verbatim} this line sets the
90     coriolis term, and represents a tank spinning at qqq
91 afe 1.3 \item Line 10, \begin{verbatim} beta=1.E-11, \end{verbatim} this line sets
92     $\beta$ (the gradient of the coriolis parameter, $f$) to $10^{-11} s^{-1}m^{-1}$
93    
94     \item Lines 15 and 16
95     \begin{verbatim}
96 afe 1.6 rigidLid=.TRUE.,
97     implicitFreeSurface=.FALSE.,
98 afe 1.3 \end{verbatim}
99 afe 1.6
100     these lines do the opposite of the following:
101     suppress the rigid lid formulation of the surface
102 afe 1.3 pressure inverter and activate the implicit free surface form
103     of the pressure inverter.
104 afe 1.1
105     \item Line 27,
106     \begin{verbatim}
107 afe 1.3 startTime=0,
108 afe 1.1 \end{verbatim}
109 afe 1.3 this line indicates that the experiment should start from $t=0$
110     and implicitly suppresses searching for checkpoint files associated
111     with restarting an numerical integration from a previously saved state.
112 afe 1.2
113 afe 1.1 \item Line 30,
114     \begin{verbatim}
115 afe 1.6 deltaT=0.1,
116 afe 1.1 \end{verbatim}
117 afe 1.6 This line sets the integration timestep to $0.1s$. This is an unsually
118     small value among the examples due to the small physical scale of the
119     experiment.
120 afe 1.1
121 afe 1.3 \item Line 39,
122 afe 1.1 \begin{verbatim}
123 afe 1.6 usingCylindricalGrid=.TRUE.,
124 afe 1.1 \end{verbatim}
125 afe 1.3 This line requests that the simulation be performed in a
126 afe 1.7 cylindrical coordinate system.
127 afe 1.1
128 afe 1.7 \item Line qqq,
129 afe 1.1 \begin{verbatim}
130 afe 1.7 dXspacing=3,
131 afe 1.1 \end{verbatim}
132 afe 1.7 This line sets the azimuthal grid spacing between each x-coordinate line
133 afe 1.3 in the discrete grid. The syntax indicates that the discrete grid
134 afe 1.7 should be comprise of $120$ grid lines each separated by $3^{\circ}$.
135    
136    
137 afe 1.1
138 afe 1.7 \item Line qqq,
139 afe 1.1 \begin{verbatim}
140 afe 1.7 dYspacing=0.01,
141 afe 1.1 \end{verbatim}
142 afe 1.7 This line sets the radial grid spacing between each $\rho$-coordinate line
143     in the discrete grid to $1cm$.
144 afe 1.1
145     \item Line 43,
146     \begin{verbatim}
147 afe 1.7 delZ=29*0.005,
148 afe 1.2 \end{verbatim}
149 afe 1.3 This line sets the vertical grid spacing between each z-coordinate line
150     in the discrete grid to $5000m$ ($5$~km).
151 afe 1.1
152     \item Line 46,
153     \begin{verbatim}
154 afe 1.7 bathyFile='bathyPol.bin',
155 afe 1.1 \end{verbatim}
156     This line specifies the name of the file from which the domain
157 afe 1.7 ``bathymetry'' (tank depth) is read. This file is a two-dimensional
158     ($x,y$) map of
159 afe 1.1 depths. This file is assumed to contain 64-bit binary numbers
160 afe 1.7 giving the depth of the model at each grid cell, ordered with the $x$
161 afe 1.1 coordinate varying fastest. The points are ordered from low coordinate
162 afe 1.7 to high coordinate for both axes. The units and orientation of the
163 afe 1.1 depths in this file are the same as used in the MITgcm code. In this
164 afe 1.7 experiment, a depth of $0m$ indicates an area outside of the tank
165     and a depth
166     f $-0.145m$ indicates the tank itself.
167 afe 1.1
168 afe 1.7 \item Line 49,
169     \begin{verbatim}
170     hydrogThetaFile='thetaPol.bin',
171     \end{verbatim}
172     This line specifies the name of the file from which the initial values
173     of $\theta$
174     are read. This file is a three-dimensional
175     ($x,y,z$) map and is enumerated and formatted in the same manner as the
176     bathymetry file.
177 afe 1.1
178 afe 1.7 \item Line qqq
179 afe 1.1 \begin{verbatim}
180 afe 1.7 tCyl = 0
181 afe 1.1 \end{verbatim}
182 afe 1.7 This line specifies the temperature in degrees Celsius of the interior
183     wall of the tank -- usually a bucket of ice water.
184    
185 afe 1.1
186     \end{itemize}
187    
188     \noindent other lines in the file {\it input/data} are standard values
189     that are described in the MITgcm Getting Started and MITgcm Parameters
190     notes.
191    
192 afe 1.2 \begin{small}
193 afe 1.5 \input{part3/case_studies/rotating_tank/input/data}
194 afe 1.2 \end{small}
195 afe 1.1
196     \subsubsection{File {\it input/data.pkg}}
197     \label{www:tutorials}
198    
199     This file uses standard default values and does not contain
200 afe 1.3 customizations for this experiment.
201 afe 1.1
202     \subsubsection{File {\it input/eedata}}
203     \label{www:tutorials}
204    
205     This file uses standard default values and does not contain
206 afe 1.3 customizations for this experiment.
207 afe 1.1
208 afe 1.6 \subsubsection{File {\it input/thetaPol.bin}}
209 afe 1.1 \label{www:tutorials}
210    
211 afe 1.6 The {\it input/thetaPol.bin} file specifies a three-dimensional ($x,y,z$)
212     map of initial values of $\theta$ in degrees Celsius.
213 afe 1.1
214 afe 1.6 \subsubsection{File {\it input/bathyPol.bin}}
215 afe 1.1 \label{www:tutorials}
216    
217    
218 afe 1.6 The {\it input/bathyPol.bin} file specifies a two-dimensional ($x,y$)
219 afe 1.1 map of depth values. For this experiment values are either
220 afe 1.6 $0m$ or {\bf -delZ}m, corresponding respectively to outside or inside of
221     the tank. The file contains a raw binary stream of data that is enumerated
222 afe 1.1 in the same way as standard MITgcm two-dimensional, horizontal arrays.
223    
224     \subsubsection{File {\it code/SIZE.h}}
225     \label{www:tutorials}
226    
227     Two lines are customized in this file for the current experiment
228    
229     \begin{itemize}
230    
231     \item Line 39,
232 afe 1.7 \begin{verbatim} sNx=120, \end{verbatim} this line sets
233 afe 1.1 the lateral domain extent in grid points for the
234     axis aligned with the x-coordinate.
235    
236     \item Line 40,
237 afe 1.7 \begin{verbatim} sNy=31, \end{verbatim} this line sets
238 afe 1.1 the lateral domain extent in grid points for the
239     axis aligned with the y-coordinate.
240    
241     \end{itemize}
242    
243     \begin{small}
244 afe 1.7 \input{part3/case_studies/rotating_tank/code/SIZE.h}
245 afe 1.1 \end{small}
246    
247     \subsubsection{File {\it code/CPP\_OPTIONS.h}}
248     \label{www:tutorials}
249    
250     This file uses standard default values and does not contain
251 afe 1.3 customizations for this experiment.
252 afe 1.1
253    
254     \subsubsection{File {\it code/CPP\_EEOPTIONS.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 1.2

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