/[MITgcm]/manual/s_examples/rotating_tank/tank.tex
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revision 1.10 by afe, Wed Oct 13 18:52:17 2004 UTC revision 1.15 by molod, Tue Jun 27 19:08:23 2006 UTC
# Line 16  Line 16 
16  \section{A Rotating Tank in Cylindrical Coordinates}  \section{A Rotating Tank in Cylindrical Coordinates}
17  \label{sect:eg-tank}  \label{sect:eg-tank}
18  \label{www:tutorials}  \label{www:tutorials}
19    \begin{rawhtml}
20  This section illustrates an example of MITgcm simulating a laboratory  <!-- CMIREDIR:eg-tank: -->
21  experiment on much smaller scales than those commonly considered in    \end{rawhtml}
 geophysical  
 fluid dynamics.  
22    
23  \subsection{Overview}  \subsection{Overview}
24  \label{www:tutorials}  \label{www:tutorials}
25                                                                                                                                                              
26                                                                                    This example configuration demonstrates using the MITgcm to simulate a
27  This example configuration demonstrates using the MITgcm to simulate  laboratory demonstration using a differentially heated rotating
28  a laboratory demonstration using a rotating tank of water with an ice  annulus of water.  The simulation is configured for a laboratory scale
29  bucket in the center. The simulation is configured for a laboratory  on a $3^{\circ}\times1\mathrm{cm}$ cyclindrical grid with twenty-nine
30  scale on a  vertical levels of 0.5cm each.  This is a typical laboratory setup for
31  $3^{\circ}$ $\times$ 20cm  illustration principles of GFD, as well as for a laboratory data
32  cyclindrical grid with twenty-nine vertical  assimilation project. The files for this experiment can be found in
33  levels.  the verification directory under rotating\_tank.
34  \\  \\
35    
36  example illustration from GFD lab here  example illustration from GFD lab here
37  \\  \\
38    
# Line 48  example illustration from GFD lab here Line 47  example illustration from GFD lab here
47  \subsection{Discrete Numerical Configuration}  \subsection{Discrete Numerical Configuration}
48  \label{www:tutorials}  \label{www:tutorials}
49    
50   The domain is discretised with   The domain is discretised with a uniform cylindrical grid spacing in
51  a uniform cylindrical grid spacing in the horizontal set to  the horizontal set to $\Delta a=1$~cm and $\Delta \phi=3^{\circ}$, so
52   $\Delta a=1$~cm and $\Delta \phi=3^{\circ}$, so  that there are 120 grid cells in the azimuthal direction and
53  that there are 120 grid cells in the azimuthal direction and thirty-one grid cells in the radial. Vertically the  thirty-one grid cells in the radial, representing a tank 62cm in
54  model is configured with twenty-nine layers of uniform 0.5cm thickness.  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  \\  \\
59  something about heat flux  something about heat flux
60    
# Line 86  are Line 88  are
88    
89  \begin{itemize}  \begin{itemize}
90    
91  \item Line 10, \begin{verbatim} viscAh=5.0E-6, \end{verbatim} this line sets  \item Lines 9-10, \begin{verbatim}
92  the Laplacian friction coefficient to $6 \times 10^{-6} m^2s^{-1}$,  viscAh=5.0E-6,
93  which is ususally  viscAz=5.0E-6,
94  low because of the small scale, presumably.... qqq  \end{verbatim}
95    
96  \item Line 19, \begin{verbatim}f0=0.5 , \end{verbatim} this line sets the  
97  coriolis term, and represents a tank spinning at 2/s  These lines set the Laplacian friction coefficient in the horizontal
98  \item Line 20, \begin{verbatim} beta=1.E-11, \end{verbatim} this line sets  and vertical, respectively.  Note that they are several orders of
99  $\beta$ (the gradient of the coriolis parameter, $f$) to $10^{-11} s^{-1}m^{-1}$  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  \item Lines 27 and 28  
117    \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  \begin{verbatim}  \begin{verbatim}
122  rigidLid=.TRUE.,  rigidLid=.TRUE.,
123  implicitFreeSurface=.FALSE.,  implicitFreeSurface=.FALSE.,
124  \end{verbatim}  \end{verbatim}
125    
126  qqq these lines do the opposite of the following:  These lines activate  the rigid lid formulation of the surface
127  suppress the rigid lid formulation of the surface  pressure inverter and suppress the implicit free surface form
 pressure inverter and activate the implicit free surface form  
128  of the pressure inverter.  of the pressure inverter.
129    
130  \item Line 44,  \item Line 40,
131  \begin{verbatim}  \begin{verbatim}
132  nIter=0,  nIter=0,
133  \end{verbatim}  \end{verbatim}
134  this line indicates that the experiment should start from $t=0$  This line indicates that the experiment should start from $t=0$ and
135  and implicitly suppresses searching for checkpoint files associated  implicitly suppresses searching for checkpoint files associated with
136  with restarting an numerical integration from a previously saved state.  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  \item Line 47,  
142    \item Line 43,
143  \begin{verbatim}  \begin{verbatim}
144  deltaT=0.1,  deltaT=0.1,
145  \end{verbatim}  \end{verbatim}
146  This line sets the integration timestep to $0.1s$.  This is an unsually  This line sets the integration timestep to $0.1s$.  This is an
147  small value among the examples due to the small physical scale of the  unsually small value among the examples due to the small physical
148  experiment.  scale of the experiment.  Using the ensemble Kalman filter to produce
149    input fields can necessitate even shorter timesteps.
150    
151  \item Line 58,  \item Line 56,
152  \begin{verbatim}  \begin{verbatim}
153  usingCylindricalGrid=.TRUE.,  usingCylindricalGrid=.TRUE.,
154  \end{verbatim}  \end{verbatim}
155  This line requests that the simulation be performed in a  This line requests that the simulation be performed in a
156  cylindrical coordinate system.  cylindrical coordinate system.
157    
158  \item Line 60,  \item Line 57,
159  \begin{verbatim}  \begin{verbatim}
160  dXspacing=3,  dXspacing=3,
161  \end{verbatim}  \end{verbatim}
162  This line sets the azimuthal grid spacing between each $x$-coordinate line  This line sets the azimuthal grid spacing between each $x$-coordinate line
163  in the discrete grid. The syntax indicates that the discrete grid  in the discrete grid. The syntax indicates that the discrete grid
164  should be comprise of $120$ grid lines each separated by $3^{\circ}$.  should be comprised of $120$ grid lines each separated by $3^{\circ}$.
165                                                                                                                                                                  
166    
167    \item Line 58,
 \item Line 61,  
168  \begin{verbatim}  \begin{verbatim}
169  dYspacing=0.01,  dYspacing=0.01,
170  \end{verbatim}  \end{verbatim}
 This line sets the radial cylindrical grid spacing between each $a$-coordinate line  
 in the discrete grid to $1cm$.  
171    
172  \item Line 62,  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  \begin{verbatim}  \begin{verbatim}
177  delZ=29*0.005,  delZ=29*0.005,
178  \end{verbatim}  \end{verbatim}
 This line sets the vertical grid spacing between each z-coordinate line  
 in the discrete grid to $5000m$ ($5$~km).  
179    
180  \item Line 68,  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  \begin{verbatim}  \begin{verbatim}
185  bathyFile='bathyPol.bin',  bathyFile='bathyPol.bin',
186  \end{verbatim}  \end{verbatim}
# Line 170  experiment, a depth of $0m$ indicates an Line 196  experiment, a depth of $0m$ indicates an
196  and a depth  and a depth
197  f $-0.145m$ indicates the tank itself.  f $-0.145m$ indicates the tank itself.
198    
199  \item Line 67,  \item Line 65,
200  \begin{verbatim}  \begin{verbatim}
201  hydrogThetaFile='thetaPol.bin',  hydrogThetaFile='thetaPol.bin',
202  \end{verbatim}  \end{verbatim}
# Line 180  are read. This file is a three-dimension Line 206  are read. This file is a three-dimension
206  ($x,y,z$) map and is enumerated and formatted in the same manner as the  ($x,y,z$) map and is enumerated and formatted in the same manner as the
207  bathymetry file.  bathymetry file.
208    
209  \item Line qqq  \item Lines 66 and 67
210  \begin{verbatim}  \begin{verbatim}
211   tCyl  = 0   tCylIn  = 0
212     tCylOut  = 20
213  \end{verbatim}  \end{verbatim}
214  This line specifies the temperature in degrees Celsius of the interior  These line specify the temperatures in degrees Celsius of the interior
215  wall of the tank -- usually a bucket of ice water.  and exterior walls of the tank -- typically taken to be icewater on
216    the inside and room temperature on the outside.
217    
218    
219  \end{itemize}  \end{itemize}
220    
221  \noindent other lines in the file {\it input/data} are standard values  \noindent Other lines in the file {\it input/data} are standard values
222  that are described in the MITgcm Getting Started and MITgcm Parameters  that are described in the MITgcm Getting Started and MITgcm Parameters
223  notes.  notes.
224    
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