<?xml version="1.0" encoding="UTF-8" ?>
<?xml-stylesheet type="text/xsl" href="https://communities.bentley.com/cfs-file/__key/system/syndication/rss.xsl" media="screen"?><rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/"><channel><title>Are Channels prismatic or non-prismatic?</title><link>https://communities.bentley.com/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/11041/are-channels-prismatic-or-non-prismatic</link><description /><dc:language>en-US</dc:language><generator>Telligent Community 12</generator><item><title>Are Channels prismatic or non-prismatic?</title><link>https://communities.bentley.com/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/11041/are-channels-prismatic-or-non-prismatic</link><pubDate>Sun, 13 Nov 2022 22:04:17 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:4157c537-b37f-46a4-a710-d5e889ad37ce</guid><dc:creator>Jesse Dringoli</dc:creator><comments>https://communities.bentley.com/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/11041/are-channels-prismatic-or-non-prismatic#comments</comments><description>Current Revision posted to OpenFlows | Water Infrastructure Wiki by Jesse Dringoli on 11/13/2022 10:04:17 PM&lt;br /&gt;
&lt;table style="background-color:#dce5f0;border:0px solid #dce5f0;width:500px;" align="left" border="0"&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;b&gt;&amp;nbsp;&lt;/b&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;span style="font-size:medium;"&gt;&lt;b&gt;Applies To&amp;nbsp;&lt;/b&gt;&lt;/span&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Product(s):&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;SewerGEMS, CivilStorm, StormCAD, SewerCAD&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Version(s):&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;08.11.XX.XX, 10.XX.XX.XX&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Area:&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;Modeling&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Original Author:&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;Jesse Dringoli, Bentley Technical Support Group&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;
&lt;h1&gt;Problem&lt;/h1&gt;
&lt;p&gt;Is the Channel link element treated as prismatic or non-prismatic? If I have a cross section node at each end, will it keep a constant geometry for the channel or will it interpolate between the geometry of the cross sections?&lt;/p&gt;
&lt;p&gt;With the Explicit (SWMM) solver, the following user notification appears when using channels:&lt;/p&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;&amp;quot;SWMM does not directly support channel elements. Non-prismatic channels are converted to SWMM style prismatic channels. The export sets the shape of the SWMM channel based on the start cross section if it exists, otherwise the stop cross section is used&amp;quot;&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;
&lt;p&gt;&lt;/p&gt;
&lt;h1&gt;Solution&lt;/h1&gt;
&lt;p&gt;The answer depends on which product or which numerical solver you are using, which is selected in the Calculation Options. There are four solvers:&lt;/p&gt;
&lt;p&gt;GVF Rational - available in StormCAD, CivilStorm and SewerGEMS&lt;br /&gt;GVF Convex - available in SewerCAD and SewerGEMS&lt;br /&gt;Implicit Dynamic - available in SewerGEMS and CivilStorm&lt;br /&gt;Explicit Dynamic (SWMM) -&amp;nbsp;available in SewerGEMS and CivilStorm&lt;/p&gt;
&lt;p&gt;Currently, with the Implicit Dynamic numerical solver, channels are treated as non-prismatic; the geometry is interpolated over the length of the channel based on the upstream and downstream cross section elements&amp;#39; geometry. The exception is if there is only one cross section node connected to the channel, in which case it uses that.&lt;/p&gt;
&lt;p&gt;With the other solvers, channels are treated as prismatic, with the geometry being constant over the length of the link, based on the Start Node&amp;#39;s cross section.&amp;nbsp;If the Start Node is not a cross section, then the geometry of the link is based on the cross section Stop Node. So for instance if you&amp;#39;re using the StormCAD or SewerCAD product, channels will always be treated as prismatic. There is no need to convert channels and cross sections to conduits and transitions as these solvers will automatically handle the channels as prismatic.&lt;span&gt;&amp;nbsp;If you have adequately spaced cross sections and relatively small changes, there should not be any notable impact of the prismatic assumption.&lt;/span&gt;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: StormCAD, channels, SewerGEMS, Cross Sections, SewerCAD, CivilStorm, prismatic&lt;/div&gt;
</description></item><item><title>Are Channels prismatic or non-prismatic?</title><link>https://communities.bentley.com/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/11041/are-channels-prismatic-or-non-prismatic/revision/4</link><pubDate>Wed, 22 Jun 2022 16:31:11 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:4157c537-b37f-46a4-a710-d5e889ad37ce</guid><dc:creator>Jesse Dringoli</dc:creator><comments>https://communities.bentley.com/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/11041/are-channels-prismatic-or-non-prismatic#comments</comments><description>Revision 4 posted to OpenFlows | Water Infrastructure Wiki by Jesse Dringoli on 6/22/2022 4:31:11 PM&lt;br /&gt;
&lt;table style="background-color:#dce5f0;border:0px solid #dce5f0;width:500px;" align="left" border="0"&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;b&gt;&amp;nbsp;&lt;/b&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;span style="font-size:medium;"&gt;&lt;b&gt;Applies To&amp;nbsp;&lt;/b&gt;&lt;/span&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Product(s):&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;SewerGEMS, CivilStorm, StormCAD, SewerCAD&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Version(s):&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;08.11.XX.XX, 10.XX.XX.XX&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Area:&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;Modeling&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Original Author:&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;Jesse Dringoli, Bentley Technical Support Group&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;
&lt;h1&gt;Problem&lt;/h1&gt;
&lt;p&gt;Is the Channel link element treated as prismatic or non-prismatic? If I have a cross section node at each end, will it keep a constant geometry for the channel or will it interpolate between the geometry of the cross sections?&lt;/p&gt;
&lt;p&gt;With the Explicit (SWMM) solver, the following user notification appears when using channels:&lt;/p&gt;
&lt;p&gt;&lt;em&gt;&lt;strong&gt;&amp;quot;SWMM does not directly support channel elements. Non-prismatic channels are converted to SWMM style prismatic channels. The export sets the shape of the SWMM channel based on the start cross section if it exists, otherwise the stop cross section is used&amp;quot;&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;
&lt;p&gt;&lt;/p&gt;
&lt;h1&gt;Solution&lt;/h1&gt;
&lt;p&gt;The answer depends on which product or which numerical solver you are using, which is selected in the Calculation Options. There are four solvers:&lt;/p&gt;
&lt;p&gt;GVF Rational - available in StormCAD, CivilStorm and SewerGEMS&lt;br /&gt;GVF Convex - available in SewerCAD and SewerGEMS&lt;br /&gt;Implicit Dynamic - available in SewerGEMS and CivilStorm&lt;br /&gt;Explicit Dynamic (SWMM) -&amp;nbsp;available in SewerGEMS and CivilStorm&lt;/p&gt;
&lt;p&gt;Currently, with the Implicit Dynamic numerical solver, channels are treated as non-prismatic; the geometry is interpolated over the length of the channel based on the upstream and downstream cross section elements&amp;#39; geometry. The exception is if there is only one cross section node connected to the channel, in which case it uses that.&lt;/p&gt;
&lt;p&gt;With the other solvers, channels are treated as prismatic, with the geometry being constant over the length of the link, based on the Start Node&amp;#39;s cross section.&amp;nbsp;If the Start Node is not a cross section, then the geometry of the link is based on the cross section Stop Node. So for instance if you&amp;#39;re using the StormCAD or SewerCAD product, channels will always be treated as prismatic.&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: StormCAD, channels, SewerGEMS, Cross Sections, SewerCAD, CivilStorm, prismatic&lt;/div&gt;
</description></item><item><title>Are Channels prismatic or non-prismatic?</title><link>https://communities.bentley.com/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/11041/are-channels-prismatic-or-non-prismatic/revision/3</link><pubDate>Thu, 12 Oct 2017 16:48:11 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:4157c537-b37f-46a4-a710-d5e889ad37ce</guid><dc:creator>Jesse Dringoli</dc:creator><comments>https://communities.bentley.com/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/11041/are-channels-prismatic-or-non-prismatic#comments</comments><description>Revision 3 posted to OpenFlows | Water Infrastructure Wiki by Jesse Dringoli on 10/12/2017 4:48:11 PM&lt;br /&gt;
&lt;table style="background-color:#dce5f0;border:0px solid #dce5f0;width:500px;" align="left" border="0"&gt;
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&lt;td style="text-align:right;"&gt;&lt;b&gt;&amp;nbsp;&lt;/b&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;span style="font-size:medium;"&gt;&lt;b&gt;Applies To&amp;nbsp;&lt;/b&gt;&lt;/span&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Product(s):&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;SewerGEMS, CivilStorm, StormCAD, SewerCAD&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Version(s):&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;08.11.XX.XX, 10.XX.XX.XX&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Area:&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;Modeling&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Original Author:&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;Jesse Dringoli, Bentley Technical Support Group&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;
&lt;h1&gt;Problem&lt;/h1&gt;
&lt;p&gt;Is the Channel link element treated as prismatic or non-prismatic? If I have a cross section node at each end, will it keep a constant geometry for the channel or will it interpolate between the geometry of the cross sections?&lt;/p&gt;
&lt;p&gt;&lt;/p&gt;
&lt;h1&gt;Solution&lt;/h1&gt;
&lt;p&gt;The answer depends on which product or which numerical solver you are using, which is selected in the Calculation Options. There are four solvers:&lt;/p&gt;
&lt;p&gt;GVF Rational - available in StormCAD, CivilStorm and SewerGEMS&lt;br /&gt;GVF Convex - available in SewerCAD and SewerGEMS&lt;br /&gt;Implicit Dynamic - available in SewerGEMS and CivilStorm&lt;br /&gt;Explicit Dynamic (SWMM) -&amp;nbsp;available in SewerGEMS and CivilStorm&lt;/p&gt;
&lt;p&gt;Currently, with the Implicit Dynamic numerical solver, channels are treated as non-prismatic; the geometry is interpolated over the length of the channel based on the upstream and downstream cross section elements&amp;#39; geometry. The exception is if there is only one cross section node connected to the channel, in which case it uses that.&lt;/p&gt;
&lt;p&gt;With the other solvers, channels are treated as prismatic, with the geometry being constant over the length of the link, based on the Start Node&amp;#39;s cross section.&amp;nbsp;If the Start Node is not a cross section, then the geometry of the link is based on the cross section Stop Node. So for instance if you&amp;#39;re using the StormCAD or SewerCAD product, channels will always be treated as prismatic.&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: StormCAD, channels, SewerGEMS, Cross Sections, SewerCAD, CivilStorm, prismatic&lt;/div&gt;
</description></item><item><title>Are Channels prismatic or non-prismatic?</title><link>https://communities.bentley.com/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/11041/are-channels-prismatic-or-non-prismatic/revision/2</link><pubDate>Tue, 12 Jul 2016 19:24:13 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:4157c537-b37f-46a4-a710-d5e889ad37ce</guid><dc:creator>Jesse Dringoli</dc:creator><comments>https://communities.bentley.com/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/11041/are-channels-prismatic-or-non-prismatic#comments</comments><description>Revision 2 posted to OpenFlows | Water Infrastructure Wiki by Jesse Dringoli on 7/12/2016 7:24:13 PM&lt;br /&gt;
&lt;h1&gt;&lt;b&gt;&lt;img style="border-width:0px;" src="/Other/Old_Site_Files/Bentley_Folders/m/support/17560/download.aspx" alt=" " height="60" width="189" /&gt;&lt;/b&gt;&lt;/h1&gt;
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&lt;tbody&gt;
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&lt;td style="text-align:right;"&gt;&lt;b&gt;&amp;nbsp;&lt;/b&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;b&gt;&amp;nbsp;&lt;/b&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;b&gt;&amp;nbsp;&lt;/b&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;span style="font-size:medium;"&gt;&lt;b&gt;Applies To&amp;nbsp;&lt;/b&gt;&lt;/span&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Product(s):&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;Bentley SewerGEMS, Bentley CivilStorm, Bentley StormCAD, Bentley SewerCAD&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Version(s):&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;08.11.03.84&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Environment:&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;N/A&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Area:&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;Modeling&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Subarea:&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Original Author:&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;Jesse Dringoli, Bentley Technical Support Group&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;td&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;
&lt;h1&gt;Problem&lt;/h1&gt;
&lt;p&gt;Is the Channel link element treated as prismatic or non-prismatic? If I have a cross section node at each end, will it keep a constant geometry for the channel or will it interpolate between the geometry of the cross sections?&lt;/p&gt;
&lt;p&gt;&lt;/p&gt;
&lt;h1&gt;Solution&lt;/h1&gt;
&lt;p&gt;The answer depends on which product or which numerical solver you are using, which is selected in the Calculation Options. There are four solvers:&lt;/p&gt;
&lt;p&gt;GVF Rational - available in StormCAD, CivilStorm and SewerGEMS&lt;br /&gt;GVF Convex - available in SewerCAD and SewerGEMS&lt;br /&gt;Implicit Dynamic - available in SewerGEMS and CivilStorm&lt;br /&gt;Explicit Dynamic (SWMM) -&amp;nbsp;available in SewerGEMS and CivilStorm&lt;/p&gt;
&lt;p&gt;Currently, with the Implicit Dynamic numerical solver, channels are treated as non-prismatic; the geometry is interpolated over the length of the channel based on the upstream and downstream cross section elements&amp;#39; geometry. The exception is if there is only one cross section node connected to the channel, in which case it uses that.&lt;/p&gt;
&lt;p&gt;With the other solvers, channels are treated as prismatic, with the geometry being constant over the length of the link, based on the Start Node&amp;#39;s cross section.&amp;nbsp;If the Start Node is not a cross section, then the geometry of the link is based on the cross section Stop Node. So for instance if you&amp;#39;re using the StormCAD or SewerCAD product, channels will always be treated as prismatic.&lt;/p&gt;
&lt;p&gt;&amp;nbsp;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: Bentley CivilStorm, channels, Cross Sections, Bentley StormCAD, prismatic, Bentley SewerGEMS, Bentley SewerCAD&lt;/div&gt;
</description></item><item><title>Are Channels prismatic or non-prismatic?</title><link>https://communities.bentley.com/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/11041/are-channels-prismatic-or-non-prismatic/revision/1</link><pubDate>Mon, 06 Jan 2014 17:25:43 GMT</pubDate><guid isPermaLink="false">6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:4157c537-b37f-46a4-a710-d5e889ad37ce</guid><dc:creator>Jesse Dringoli</dc:creator><comments>https://communities.bentley.com/products/hydraulics___hydrology/w/hydraulics_and_hydrology__wiki/11041/are-channels-prismatic-or-non-prismatic#comments</comments><description>Revision 1 posted to OpenFlows | Water Infrastructure Wiki by Jesse Dringoli on 1/6/2014 5:25:43 PM&lt;br /&gt;
&lt;h1&gt;&lt;b&gt;&lt;img style="border-width:0px;" src="/Other/Old_Site_Files/Bentley_Folders/m/support/17560/download.aspx" alt=" " height="60" width="189" /&gt;&lt;/b&gt;&lt;/h1&gt;
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&lt;td style="text-align:right;"&gt;&lt;b&gt;&amp;nbsp;&lt;/b&gt;&lt;/td&gt;
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&lt;td style="text-align:right;"&gt;&lt;span style="font-size:medium;"&gt;&lt;b&gt;Applies To&amp;nbsp;&lt;/b&gt;&lt;/span&gt;&lt;/td&gt;
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&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
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&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Product(s):&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;Bentley SewerGEMS, Bentley CivilStorm, Bentley StormCAD, Bentley SewerCAD&lt;/td&gt;
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&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Version(s):&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;08.11.03.84&lt;/td&gt;
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&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Environment:&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;N/A&lt;/td&gt;
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&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Area:&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;Modeling&lt;/td&gt;
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&lt;td style="text-align:right;"&gt;&lt;strong&gt;Subarea:&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
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&lt;td style="text-align:right;"&gt;&lt;strong&gt;&amp;nbsp;&lt;/strong&gt;&lt;/td&gt;
&lt;td style="text-align:right;"&gt;&lt;strong&gt;Original Author:&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;Jesse Dringoli, Bentley Technical Support Group&lt;/td&gt;
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&lt;h1&gt;&lt;/h1&gt;
&lt;h1&gt;Problem&lt;/h1&gt;
&lt;p&gt;Is the Channel link element treated as prismatic or non-prismatic? If I have a cross section node at each end, will it keep a constant geometry for the channel or will it interpolate between the geometry of the cross sections?&lt;/p&gt;
&lt;p&gt;&lt;/p&gt;
&lt;h1&gt;Solution&lt;/h1&gt;
&lt;p&gt;The answer depends on which product or which numerical solver you are using, which is selected in the Calculation Options. There are four solvers:&lt;/p&gt;
&lt;p&gt;GVF Rational - available in StormCAD, CivilStorm and SewerGEMS&lt;br /&gt;GVF Convex - available in SewerCAD and SewerGEMS&lt;br /&gt;Implicit Dynamic - available in SewerGEMS and CivilStorm&lt;br /&gt;Explicit Dynamic (SWMM) -&amp;nbsp;available in SewerGEMS and CivilStorm&lt;/p&gt;
&lt;p&gt;Currently, with the Implicit Dynamic numerical solver, channels are treated as non-prismatic; the geometry is interpolated over the length of the channel based on the upstream and downstream cross section elements&amp;#39; geometry. The exception is if there is only one cross section node connected to the channel, in which case it uses that.&lt;/p&gt;
&lt;p&gt;With the other solvers, channels are treated as prismatic, with the geometry being constant over the length of the link, based on the Start Node&amp;#39;s cross section.&amp;nbsp;If the Start Node is not a cross section, then the geometry of the link is based on the cross section Stop Node. So for instance if you&amp;#39;re using the StormCAD or SewerCAD product, channels will always be treated as prismatic.&lt;/p&gt;
&lt;p&gt;&amp;nbsp;&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;

&lt;div style="font-size: 90%;"&gt;Tags: Bentley CivilStorm, channels, Cross Sections, Bentley StormCAD, prismatic, Bentley SewerGEMS, Bentley SewerCAD&lt;/div&gt;
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