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<p>Hello MITgcm-ers,</p>
<p>I am trying to set up a step change in the OBC (at the southern
boundary) for a flow problem with no surface forcing. A sponge
layer is prescribed at the southern boundary in order to absorb an
outflow at that boundary. An inflow is prescribed along the same
boundary but at another location than the outflow. The desired
step change is the magnitude of the inflow (from 0 to 50 Sv).<br>
</p>
<p>Here is the current set-up:<br>
</p>
<p>1) code/packages.conf includes gfd, cal, exf, and obcs</p>
<p>2) /input/data.pkg:<br>
</p>
<font size="-1">&PACKAGES</font><br>
<font size="-1">useCAL=.TRUE.,</font><br>
<font size="-1">useEXF=.TRUE.,</font><br>
<font size="-1">useOBCS=.TRUE.,</font><br>
<font size="-1">&</font><br>
<p>3) input/data.cal:<br>
</p>
<font size="-1">&CAL_NML</font><br>
<font size="-1">The Calendar='model',</font><br>
<font size="-1">startDate_1=0000101,</font><br>
<font size="-1">startDate_2=000000,</font><br>
<font size="-1">&</font>
<p>4) input/data.exf:<br>
</p>
<font size="-1">&EXF_NML_01<br>
&<br>
&EXF_NML_02<br>
&<br>
&EXF_NML_03<br>
&<br>
&EXF_NML_OBCS<br>
obcsSstartdate1=0000101,<br>
obcsSstartdate2=000000,<br>
obcsSperiod=432000., (i.e., step change desired after 5 days of
integration)<br>
&</font>
<p>5) input/data.obcs:<br>
</p>
<font size="-1">&OBCS_PARM01</font><br>
<font size="-1">...</font><br>
<font size="-1">useOBCSprescribe=.TRUE.,</font><br>
<font size="-1">useOBCSsponge=.TRUE.,</font><br>
<font size="-1">OBCSsponge_S=.TRUE.,</font><br>
<font size="-1">...</font><br>
<font size="-1">OBCSuFile = 'uSouth.bin',</font><br>
<font size="-1">OBCSvFile = 'vSouth.bin',</font><br>
<font size="-1">OBCStFile = 'tSouth.bin',</font><br>
<font size="-1">OBCSsFile = 'sSouth.bin'</font><br>
<font size="-1">&</font><br>
<font size="-1"></font><br>
<font size="-1">&OBCS_PARM03</font><br>
<font size="-1">spongeThickness=10,</font><br>
<font size="-1">Urelaxobcsinner=43200.,</font><br>
<font size="-1">Urelaxobcsbound=8640.,</font><br>
<font size="-1">Vrelaxobcsinner=43200.,</font><br>
<font size="-1">Vrelaxobcsbound=8640.,</font><br>
<font size="-1">&</font><br>
<p>The .bin files in input/data.obcs contain fields for two time
slices produced from input/gendata.m.</p>
<p>Here is the issue: the run blows up after 1 iteration ("SOLUTION
IS HEADING OUT OF BOUNDS"). Use of a ridiculously small time step
(deltaT well below CFL criterion) yields a similar result. If no
step change is prescribed (inflow fixed at 50 Sv from the start of
the run), then the run goes fine.<br>
</p>
<p>Could anyone help me understand this result? <br>
</p>
<p>Thanks for any pointers,<br>
</p>
<p>Olivier.<br>
</p>
<p><br>
</p>
<p><br>
</p>
<p><br>
</p>
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