/[MITgcm]/manual/s_examples/rotating_tank/tank.tex
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1 molod 1.15 % $Header: /u/gcmpack/manual/part3/case_studies/rotating_tank/tank.tex,v 1.14 2006/04/08 01:50:50 edhill 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 edhill 1.11 \begin{rawhtml}
20     <!-- CMIREDIR:eg-tank: -->
21     \end{rawhtml}
22 afe 1.2
23 afe 1.4 \subsection{Overview}
24     \label{www:tutorials}
25 afe 1.12
26     This example configuration demonstrates using the MITgcm to simulate a
27     laboratory demonstration using a differentially heated rotating
28     annulus of water. The simulation is configured for a laboratory scale
29 edhill 1.14 on a $3^{\circ}\times1\mathrm{cm}$ cyclindrical grid with twenty-nine
30 afe 1.12 vertical levels of 0.5cm each. This is a typical laboratory setup for
31     illustration principles of GFD, as well as for a laboratory data
32 molod 1.15 assimilation project. The files for this experiment can be found in
33     the verification directory under rotating\_tank.
34 afe 1.4 \\
35 afe 1.12
36 afe 1.10 example illustration from GFD lab here
37     \\
38 afe 1.4
39    
40 afe 1.2
41 afe 1.3
42    
43     \subsection{Equations Solved}
44     \label{www:tutorials}
45 afe 1.1
46 afe 1.3
47     \subsection{Discrete Numerical Configuration}
48     \label{www:tutorials}
49    
50 afe 1.12 The domain is discretised with a uniform cylindrical grid spacing in
51     the horizontal set to $\Delta a=1$~cm and $\Delta \phi=3^{\circ}$, so
52     that there are 120 grid cells in the azimuthal direction and
53     thirty-one grid cells in the radial, representing a tank 62cm in
54     diameter. The bathymetry file sets the depth=0 in the nine lowest
55     radial rows to represent the central of the annulus. Vertically the
56     model is configured with twenty-nine layers of uniform 0.5cm
57     thickness.
58 afe 1.10 \\
59     something about heat flux
60 afe 1.2
61 afe 1.3 \subsection{Code Configuration}
62 afe 1.1 \label{www:tutorials}
63 afe 1.3 \label{SEC:eg-baro-code_config}
64 afe 1.1
65 afe 1.5 The model configuration for this experiment resides under the
66     directory {\it verification/rotatingi\_tank/}. The experiment files
67 afe 1.1 \begin{itemize}
68     \item {\it input/data}
69     \item {\it input/data.pkg}
70     \item {\it input/eedata},
71 afe 1.5 \item {\it input/bathyPol.bin},
72     \item {\it input/thetaPol.bin},
73 afe 1.1 \item {\it code/CPP\_EEOPTIONS.h}
74     \item {\it code/CPP\_OPTIONS.h},
75 afe 1.5 \item {\it code/SIZE.h}.
76 afe 1.1 \end{itemize}
77 afe 1.5
78 afe 1.3 contain the code customizations and parameter settings for this
79 afe 1.1 experiments. Below we describe the customizations
80     to these files associated with this experiment.
81    
82     \subsubsection{File {\it input/data}}
83     \label{www:tutorials}
84    
85     This file, reproduced completely below, specifies the main parameters
86     for the experiment. The parameters that are significant for this configuration
87     are
88    
89     \begin{itemize}
90    
91 afe 1.12 \item Lines 9-10, \begin{verbatim}
92     viscAh=5.0E-6,
93     viscAz=5.0E-6,
94     \end{verbatim}
95    
96    
97     These lines set the Laplacian friction coefficient in the horizontal
98     and vertical, respectively. Note that they are several orders of
99     magnitude smaller than the other examples due to the small scale of
100     this example.
101    
102     \item Lines 13-16, \begin{verbatim}
103     diffKhT=2.5E-6,
104     diffKzT=2.5E-6,
105     diffKhS=1.0E-6,
106     diffKzS=1.0E-6,
107    
108     \end{verbatim}
109    
110    
111     These lines set horizontal and vertical diffusion coefficients for
112     temperature and salinity. Similarly to the friction coefficients, the
113     values are a couple of orders of magnitude less than most
114     configurations.
115    
116 afe 1.3
117 afe 1.12 \item Line 17, \begin{verbatim}f0=0.5 , \end{verbatim} this line sets the
118     coriolis term, and represents a tank spinning at about 2.4 rpm.
119    
120     \item Lines 23 and 24
121 afe 1.3 \begin{verbatim}
122 afe 1.6 rigidLid=.TRUE.,
123     implicitFreeSurface=.FALSE.,
124 afe 1.3 \end{verbatim}
125 afe 1.6
126 afe 1.12 These lines activate the rigid lid formulation of the surface
127     pressure inverter and suppress the implicit free surface form
128 afe 1.3 of the pressure inverter.
129 afe 1.1
130 afe 1.12 \item Line 40,
131 afe 1.1 \begin{verbatim}
132 afe 1.10 nIter=0,
133 afe 1.1 \end{verbatim}
134 afe 1.12 This line indicates that the experiment should start from $t=0$ and
135     implicitly suppresses searching for checkpoint files associated with
136     restarting an numerical integration from a previously saved state.
137     Instead, the file thetaPol.bin will be loaded to initialized the
138     temperature fields as indicated below, and other variables will be
139     initialized to their defaults.
140    
141 afe 1.2
142 afe 1.12 \item Line 43,
143 afe 1.1 \begin{verbatim}
144 afe 1.6 deltaT=0.1,
145 afe 1.1 \end{verbatim}
146 afe 1.12 This line sets the integration timestep to $0.1s$. This is an
147     unsually small value among the examples due to the small physical
148     scale of the experiment. Using the ensemble Kalman filter to produce
149     input fields can necessitate even shorter timesteps.
150 afe 1.1
151 afe 1.12 \item Line 56,
152 afe 1.1 \begin{verbatim}
153 afe 1.6 usingCylindricalGrid=.TRUE.,
154 afe 1.1 \end{verbatim}
155 afe 1.3 This line requests that the simulation be performed in a
156 afe 1.7 cylindrical coordinate system.
157 afe 1.1
158 afe 1.12 \item Line 57,
159 afe 1.1 \begin{verbatim}
160 afe 1.7 dXspacing=3,
161 afe 1.1 \end{verbatim}
162 afe 1.10 This line sets the azimuthal grid spacing between each $x$-coordinate line
163 afe 1.3 in the discrete grid. The syntax indicates that the discrete grid
164 afe 1.12 should be comprised of $120$ grid lines each separated by $3^{\circ}$.
165    
166 afe 1.7
167 afe 1.12 \item Line 58,
168 afe 1.1 \begin{verbatim}
169 afe 1.7 dYspacing=0.01,
170 afe 1.1 \end{verbatim}
171    
172 afe 1.12 This line sets the radial cylindrical grid spacing between each
173     $a$-coordinate line in the discrete grid to $1cm$.
174    
175     \item Line 59,
176 afe 1.1 \begin{verbatim}
177 afe 1.7 delZ=29*0.005,
178 afe 1.2 \end{verbatim}
179 afe 1.1
180 afe 1.12 This line sets the vertical grid spacing between each of 29
181     z-coordinate lines in the discrete grid to $0.005m$ ($5$~mm).
182    
183     \item Line 64,
184 afe 1.1 \begin{verbatim}
185 afe 1.7 bathyFile='bathyPol.bin',
186 afe 1.1 \end{verbatim}
187     This line specifies the name of the file from which the domain
188 afe 1.7 ``bathymetry'' (tank depth) is read. This file is a two-dimensional
189 afe 1.10 ($a,\phi$) map of
190 afe 1.1 depths. This file is assumed to contain 64-bit binary numbers
191 afe 1.10 giving the depth of the model at each grid cell, ordered with the $\phi$
192 afe 1.1 coordinate varying fastest. The points are ordered from low coordinate
193 afe 1.7 to high coordinate for both axes. The units and orientation of the
194 afe 1.1 depths in this file are the same as used in the MITgcm code. In this
195 afe 1.7 experiment, a depth of $0m$ indicates an area outside of the tank
196     and a depth
197     f $-0.145m$ indicates the tank itself.
198 afe 1.1
199 afe 1.12 \item Line 65,
200 afe 1.7 \begin{verbatim}
201     hydrogThetaFile='thetaPol.bin',
202     \end{verbatim}
203     This line specifies the name of the file from which the initial values
204 afe 1.10 of temperature
205 afe 1.7 are read. This file is a three-dimensional
206     ($x,y,z$) map and is enumerated and formatted in the same manner as the
207     bathymetry file.
208 afe 1.1
209 afe 1.13 \item Lines 66 and 67
210 afe 1.1 \begin{verbatim}
211 afe 1.12 tCylIn = 0
212     tCylOut = 20
213 afe 1.1 \end{verbatim}
214 afe 1.12 These line specify the temperatures in degrees Celsius of the interior
215     and exterior walls of the tank -- typically taken to be icewater on
216 afe 1.13 the inside and room temperature on the outside.
217 afe 1.7
218 afe 1.1
219     \end{itemize}
220    
221 afe 1.12 \noindent Other lines in the file {\it input/data} are standard values
222 afe 1.1 that are described in the MITgcm Getting Started and MITgcm Parameters
223     notes.
224    
225 afe 1.2 \begin{small}
226 afe 1.5 \input{part3/case_studies/rotating_tank/input/data}
227 afe 1.2 \end{small}
228 afe 1.1
229     \subsubsection{File {\it input/data.pkg}}
230     \label{www:tutorials}
231    
232     This file uses standard default values and does not contain
233 afe 1.3 customizations for this experiment.
234 afe 1.1
235     \subsubsection{File {\it input/eedata}}
236     \label{www:tutorials}
237    
238     This file uses standard default values and does not contain
239 afe 1.3 customizations for this experiment.
240 afe 1.1
241 afe 1.6 \subsubsection{File {\it input/thetaPol.bin}}
242 afe 1.1 \label{www:tutorials}
243    
244 afe 1.6 The {\it input/thetaPol.bin} file specifies a three-dimensional ($x,y,z$)
245 afe 1.10 map of initial values of $\theta$ in degrees Celsius. This particular
246     experiment is set to random values x around 20C to provide initial
247     perturbations.
248 afe 1.1
249 afe 1.6 \subsubsection{File {\it input/bathyPol.bin}}
250 afe 1.1 \label{www:tutorials}
251    
252    
253 afe 1.6 The {\it input/bathyPol.bin} file specifies a two-dimensional ($x,y$)
254 afe 1.1 map of depth values. For this experiment values are either
255 afe 1.6 $0m$ or {\bf -delZ}m, corresponding respectively to outside or inside of
256     the tank. The file contains a raw binary stream of data that is enumerated
257 afe 1.1 in the same way as standard MITgcm two-dimensional, horizontal arrays.
258    
259     \subsubsection{File {\it code/SIZE.h}}
260     \label{www:tutorials}
261    
262     Two lines are customized in this file for the current experiment
263    
264     \begin{itemize}
265    
266     \item Line 39,
267 afe 1.7 \begin{verbatim} sNx=120, \end{verbatim} this line sets
268 afe 1.1 the lateral domain extent in grid points for the
269     axis aligned with the x-coordinate.
270    
271     \item Line 40,
272 afe 1.7 \begin{verbatim} sNy=31, \end{verbatim} this line sets
273 afe 1.1 the lateral domain extent in grid points for the
274     axis aligned with the y-coordinate.
275    
276     \end{itemize}
277    
278     \begin{small}
279 afe 1.7 \input{part3/case_studies/rotating_tank/code/SIZE.h}
280 afe 1.1 \end{small}
281    
282     \subsubsection{File {\it code/CPP\_OPTIONS.h}}
283     \label{www:tutorials}
284    
285     This file uses standard default values and does not contain
286 afe 1.3 customizations for this experiment.
287 afe 1.1
288    
289     \subsubsection{File {\it code/CPP\_EEOPTIONS.h}}
290     \label{www:tutorials}
291    
292     This file uses standard default values and does not contain
293 afe 1.3 customizations for this experiment.
294 afe 1.2

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