# 
msgid ""
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"Project-Id-Version: Modelica by Example 0.2.1\n"
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"Language-Team: LANGUAGE <LL@li.org>\n"
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#: ../../source/components/connectors/simple_domains.rst:4
msgid "Simple Domains"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:6
msgid ""
"In this section, we'll discuss relatively simple engineering domains. These "
"are ones where a ``connector`` deals with only one through and one across "
"variable.  Conceptually, this means that only one conserved quantity is "
"involved with that connector."
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:11
msgid ""
"The following table covers four different engineering domains.  In each "
"domain, we see the choice of through and across variables that we will be "
"using along with the SI units for those quantities."
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:16
msgid "Domain"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:16
msgid "Through Variable"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:16
msgid "Across Variable"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:18
#: ../../source/components/connectors/simple_domains.rst:52
msgid "Electrical"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:18
msgid "Current [A]"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:18
msgid "Voltage [V]"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:19
#: ../../source/components/connectors/simple_domains.rst:84
msgid "Thermal"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:19
msgid "Heat [W]"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:19
msgid "Temperature [K]"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:20
#: ../../source/components/connectors/simple_domains.rst:111
msgid "Translational"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:20
msgid "Force [N]"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:20
msgid "Position [m]"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:21
#: ../../source/components/connectors/simple_domains.rst:135
msgid "Rotational"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:21
msgid "Torque [N.m]"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:21
msgid "Angle [rad]"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:24
msgid ""
"You may have seen a similar table before with slightly different choices.  "
"For example, you will sometimes see velocity (in :math:`m/s`) chosen as the "
"across variable for translational motion. The choices above are guided by "
"two constraints."
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:29
msgid ""
"The first constraint is that the through variable should be the time "
"derivative of some conserved quantity.  The reason for this constraint is "
"that the through variable will be used to formulate generalized conservation"
" equations in our system.  As such, it is essential that the through "
"variables be conserved quantities."
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:35
msgid ""
"The second constraint is that the across variable should be the lowest order"
" derivative to appear in any of our constitutive or empirical equations in "
"the domain.  So, for example, we chose position for translational motion "
"because position is used in describing the behavior of a spring (*i.e.,* "
"Hooke's law).  If we had chosen velocity (the derivative of position with "
"respect to time), then we would have been in the awkward situation of trying"
" to describe the behavior of a spring in terms of velocities, not positions."
"  An essential point here is that **differentiation is lossy**.  If we know "
"position, we can easily express velocity.  But if we only know velocity, we "
"cannot compute position without knowing an additional integration constant. "
"This is why we want to work with across variables that have not been overly "
"differentiated."
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:49
msgid "Now let's look at each domain individually."
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:54
msgid "We can define a ``connector`` for the electrical domain as follows:"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:60
msgid ""
"Here we see that the variable ``v`` in this connector represents the voltage"
" and the variable ``i`` represents the current."
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:65
msgid ""
"Note the presence of the ``flow`` qualifier in the declaration of ``i``, the"
" current.  The ``flow`` qualifier is what tells the Modelica compiler that "
"``i`` is the through variable.  Recall from our discussion on :ref:`acausal-"
"connections` that the ``flow`` variable should be the time derivative of a "
"conserved quantity.  We can see that this connector follows that convention,"
" since ``Current`` is the time derivative of charge (and charge is a "
"conserved quantity)."
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:73
msgid ""
"Note the absence of any qualifier in the declaration of ``v``, the voltage."
"  A variable without any qualifier is assumed to be the ``across`` variable."
"  You will find a more complete discussion about :ref:`connector-vars` "
"(including the various qualifiers that can applied to them) later in this "
"chapter."
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:79
msgid ""
"The interested reader may wish to jump ahead to our discussion of :ref"
":`electrical-components` to see how we build on the connector definition to "
"create electrical circuit components."
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:86
msgid ""
"A connector for modeling lumped heat transfer isn't much different from an "
"electrical connector:"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:93
msgid ""
"Instead of ``Voltage`` and ``Current``, this connector includes "
"``Temperature`` and ``HeatFlowRate``.  While the names are different, the "
"overall structure is essentially the same.  The ``connector`` includes one "
"through variable (``q``, indicated by the presence of the ``flow`` "
"qualifier) and one across variable (``T``, indicated by the lack of any "
"qualifier).  Again, we see that the type of the variable with the ``flow`` "
"qualifier, ``HeatFlowRate``, is the time derivative of a conserved quantity,"
" energy."
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:102
msgid ""
"An example of how such a connector can be used to build components for "
"lumped thermal network modeling can be found in the upcoming discussion on "
":ref:`heat-transfer-components`.  If you feel comfortable with this "
"``connector`` definition, feel free to jump ahead.  It would still be a good"
" idea to read the :ref:`connector-review` section of the :ref:`connectors` "
"chapter at some point."
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:113
msgid "To model translational motion, we would define a connector as follows:"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:119
msgid ""
"Again, we see the same basic structure as before.  The connector contains "
"one through variable, ``f``, and one across variable ``x``. Note that, "
"although this is a one-dimensional mechanical connector, the physical types "
"are specific to translational motion and distinct from the physical types "
"used from the :ref:`rotational-connector` case to be presented next."
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:126
msgid ""
"An important fact about mechanical connectors that is often overlooked is "
"that the ``flow`` variable **is** the time derivative of a conserved "
"quantity.  For example, in the case of translational motion the ``flow`` "
"variable, ``f``, is a force and force is the time derivative of (linear) "
"momentum and momentum is a conserved quantity."
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:137
msgid ""
"For systems whose motion is constrained to be rotational, the following "
"Modelica ``connector`` definition should be used:"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:144
msgid ""
"Here we see that the across variable is ``phi`` (representing the angular "
"displacement) and the through variable is ``torque``.  As with all previous "
"examples, the ``flow`` variable is the time derivative of a conserved "
"quantity.  In this case, that conserved quantity is angular momentum."
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:151
msgid "``SimpleDomains``"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:153
msgid ""
"All the connectors defined in this section are grouped, for future "
"reference, into a single package:"
msgstr ""

#: ../../source/components/connectors/simple_domains.rst:63
msgid "flow"
msgstr ""
