[Nektar-users] About Periodic Conditions

26 May 2015

      Dear All,
I am trying to using the periodic condition within the CompressibleFlowSolver. I have tested the IsentropicVortex case with periodic conditions imposed at all boundaries. The xml file(attached with this mail) was generated with MeshConvert from a Gmesh file. I found out that in the <COMPOSITE> part, the listing order of the faces on a pair of periodic boundaries must be one-to-one correspondance, otherwise the boundary condition will not be applied correctly. However, MeshConvert seems not to be able to ensure the correct orders. For example, 

Wrong(generated directly by MeshConvert):
           <C ID="2"> F[14,4,31,23] </C>
            <C ID="3"> F[8,17,26,33] </C>
            <C ID="4"> F[1,7,20,25] </C>
            <C ID="5"> F[18,13,34,30] </C>
            <C ID="6"> F[0,6,11,16] </C>
            <C ID="7"> F[24,28,32,35] </C>
Correct(modified manually):
           <C ID="2"> F[14,4,31,23] </C>
            <C ID="3"> F[17,8,33,26] </C>
            <C ID="4"> F[1,7,20,25] </C>
            <C ID="5"> F[13,18,30,34] </C>
            <C ID="6"> F[0,6,11,16] </C>
            <C ID="7"> F[24,28,32,35] </C>

I further checked the MeshConvert , and found out that at line 339 of the file 'OutputNekpp.cpp', there is a comment "Ensure that this composite is not used for periodic BCs!". Does this mean that MeshConvert can not be used when periodic BCs exist? 
Thank you in advance!
Best wishes,
Jian YU

<?xml version="1.0" encoding="utf-8" ?>
<NEKTAR>
    <GEOMETRY DIM="3" SPACE="3">
        <VERTEX>
            <V ID="0">0.00000000e+00 -5.00000000e+00 0.00000000e+00</V>
            <V ID="1">5.00000000e+00 -5.00000000e+00 0.00000000e+00</V>
            <V ID="2">5.00000000e+00 0.00000000e+00 0.00000000e+00</V>
            <V ID="3">0.00000000e+00 0.00000000e+00 0.00000000e+00</V>
            <V ID="4">0.00000000e+00 -5.00000000e+00 5.00000000e+00</V>
            <V ID="5">5.00000000e+00 -5.00000000e+00 5.00000000e+00</V>
            <V ID="6">5.00000000e+00 0.00000000e+00 5.00000000e+00</V>
            <V ID="7">0.00000000e+00 0.00000000e+00 5.00000000e+00</V>
            <V ID="8">1.00000000e+01 -5.00000000e+00 0.00000000e+00</V>
            <V ID="9">1.00000000e+01 0.00000000e+00 0.00000000e+00</V>
            <V ID="10">1.00000000e+01 -5.00000000e+00 5.00000000e+00</V>
            <V ID="11">1.00000000e+01 0.00000000e+00 5.00000000e+00</V>
            <V ID="12">5.00000000e+00 5.00000000e+00 0.00000000e+00</V>
            <V ID="13">0.00000000e+00 5.00000000e+00 0.00000000e+00</V>
            <V ID="14">5.00000000e+00 5.00000000e+00 5.00000000e+00</V>
            <V ID="15">0.00000000e+00 5.00000000e+00 5.00000000e+00</V>
            <V ID="16">1.00000000e+01 5.00000000e+00 0.00000000e+00</V>
            <V ID="17">1.00000000e+01 5.00000000e+00 5.00000000e+00</V>
            <V ID="18">0.00000000e+00 -5.00000000e+00 1.00000000e+01</V>
            <V ID="19">5.00000000e+00 -5.00000000e+00 1.00000000e+01</V>
            <V ID="20">5.00000000e+00 0.00000000e+00 1.00000000e+01</V>
            <V ID="21">0.00000000e+00 0.00000000e+00 1.00000000e+01</V>
            <V ID="22">1.00000000e+01 -5.00000000e+00 1.00000000e+01</V>
            <V ID="23">1.00000000e+01 0.00000000e+00 1.00000000e+01</V>
            <V ID="24">5.00000000e+00 5.00000000e+00 1.00000000e+01</V>
            <V ID="25">0.00000000e+00 5.00000000e+00 1.00000000e+01</V>
            <V ID="26">1.00000000e+01 5.00000000e+00 1.00000000e+01</V>
        </VERTEX>
        <EDGE>
            <E ID="0">    0  1   </E>
            <E ID="1">    1  2   </E>
            <E ID="2">    2  3   </E>
            <E ID="3">    3  0   </E>
            <E ID="4">    0  4   </E>
            <E ID="5">    1  5   </E>
            <E ID="6">    2  6   </E>
            <E ID="7">    3  7   </E>
            <E ID="8">    4  5   </E>
            <E ID="9">    5  6   </E>
            <E ID="10">    6  7   </E>
            <E ID="11">    7  4   </E>
            <E ID="12">    1  8   </E>
            <E ID="13">    8  9   </E>
            <E ID="14">    9  2   </E>
            <E ID="15">    8  10   </E>
            <E ID="16">    9  11   </E>
            <E ID="17">    5  10   </E>
            <E ID="18">   10  11   </E>
            <E ID="19">   11  6   </E>
            <E ID="20">    2  12   </E>
            <E ID="21">   12  13   </E>
            <E ID="22">   13  3   </E>
            <E ID="23">   12  14   </E>
            <E ID="24">   13  15   </E>
            <E ID="25">    6  14   </E>
            <E ID="26">   14  15   </E>
            <E ID="27">   15  7   </E>
            <E ID="28">    9  16   </E>
            <E ID="29">   16  12   </E>
            <E ID="30">   16  17   </E>
            <E ID="31">   11  17   </E>
            <E ID="32">   17  14   </E>
            <E ID="33">    4  18   </E>
            <E ID="34">    5  19   </E>
            <E ID="35">    6  20   </E>
            <E ID="36">    7  21   </E>
            <E ID="37">   18  19   </E>
            <E ID="38">   19  20   </E>
            <E ID="39">   20  21   </E>
            <E ID="40">   21  18   </E>
            <E ID="41">   10  22   </E>
            <E ID="42">   11  23   </E>
            <E ID="43">   19  22   </E>
            <E ID="44">   22  23   </E>
            <E ID="45">   23  20   </E>
            <E ID="46">   14  24   </E>
            <E ID="47">   15  25   </E>
            <E ID="48">   20  24   </E>
            <E ID="49">   24  25   </E>
            <E ID="50">   25  21   </E>
            <E ID="51">   17  26   </E>
            <E ID="52">   23  26   </E>
            <E ID="53">   26  24   </E>
        </EDGE>
        <FACE>
            <Q ID="0">         0         1         2         3</Q>
            <Q ID="1">         0         5         8         4</Q>
            <Q ID="2">         1         6         9         5</Q>
            <Q ID="3">         2         6        10         7</Q>
            <Q ID="4">         3         7        11         4</Q>
            <Q ID="5">         8         9        10        11</Q>
            <Q ID="6">        12        13        14         1</Q>
            <Q ID="7">        12        15        17         5</Q>
            <Q ID="8">        13        16        18        15</Q>
            <Q ID="9">        14        16        19         6</Q>
            <Q ID="10">        17        18        19         9</Q>
            <Q ID="11">         2        20        21        22</Q>
            <Q ID="12">        20        23        25         6</Q>
            <Q ID="13">        21        23        26        24</Q>
            <Q ID="14">        22        24        27         7</Q>
            <Q ID="15">        10        25        26        27</Q>
            <Q ID="16">        14        28        29        20</Q>
            <Q ID="17">        28        30        31        16</Q>
            <Q ID="18">        29        30        32        23</Q>
            <Q ID="19">        19        31        32        25</Q>
            <Q ID="20">         8        34        37        33</Q>
            <Q ID="21">         9        35        38        34</Q>
            <Q ID="22">        10        35        39        36</Q>
            <Q ID="23">        11        36        40        33</Q>
            <Q ID="24">        37        38        39        40</Q>
            <Q ID="25">        17        41        43        34</Q>
            <Q ID="26">        18        42        44        41</Q>
            <Q ID="27">        19        42        45        35</Q>
            <Q ID="28">        43        44        45        38</Q>
            <Q ID="29">        25        46        48        35</Q>
            <Q ID="30">        26        46        49        47</Q>
            <Q ID="31">        27        47        50        36</Q>
            <Q ID="32">        39        48        49        50</Q>
            <Q ID="33">        31        51        52        42</Q>
            <Q ID="34">        32        51        53        46</Q>
            <Q ID="35">        45        52        53        48</Q>
        </FACE>
        <ELEMENT>
            <H ID="0">    0     1     2     3     4     5 </H>
            <H ID="1">    6     7     8     9     2    10 </H>
            <H ID="2">   11     3    12    13    14    15 </H>
            <H ID="3">   16     9    17    18    12    19 </H>
            <H ID="4">    5    20    21    22    23    24 </H>
            <H ID="5">   10    25    26    27    21    28 </H>
            <H ID="6">   15    22    29    30    31    32 </H>
            <H ID="7">   19    27    33    34    29    35 </H>
        </ELEMENT>
        <COMPOSITE>
            <C ID="1"> H[0-7] </C>
            <C ID="2"> F[14,4,31,23] </C>
            <C ID="3"> F[8,17,26,33] </C>
            <C ID="4"> F[1,7,20,25] </C>
            <C ID="5"> F[18,13,34,30] </C>
            <C ID="6"> F[0,6,11,16] </C>
            <C ID="7"> F[24,28,32,35] </C>
        </COMPOSITE>
        <DOMAIN> C[1] </DOMAIN>
    </GEOMETRY>
    <EXPANSIONS>
         <E COMPOSITE="C[1]" NUMMODES="15" FIELDS="rho,rhou,rhov,rhow,E" TYPE="MODIFIED" />
    </EXPANSIONS>
      <CONDITIONS>

        <PARAMETERS>
            <P> FinTime         = 10.         </P>
            <P> TimeStep        = 0.002         </P>
            <P> NumSteps        = 0        </P>
            <P> IO_CheckSteps   = 500      </P>
            <P> IO_InfoSteps    = 1       </P>
            <P> Gamma           = 1.4       </P>
            <P> pInf            = 101325    </P>
            <P> rhoInf          = 1.225     </P>
            <P> uInf            = 0.1       </P>
            <P> vInf            = 0.0       </P>
            <P> wInf            = 0.0       </P>
            <P> CFL             = 0     </P>
        </PARAMETERS>

        <SOLVERINFO>
            <I PROPERTY="EQType"                VALUE="EulerCFE"            />
            <I PROPERTY="Projection"            VALUE="DisContinuous"       />
            <I PROPERTY="AdvectionType"         VALUE="WeakDG"              />
            <I PROPERTY="TimeIntegrationMethod" VALUE="ClassicalRungeKutta4"/>
            <I PROPERTY="UpwindType"            VALUE="ExactToro"               />
            <I PROPERTY="ProblemType"           VALUE="IsentropicVortex"    />
        </SOLVERINFO>

        <VARIABLES>
            <V ID="0"> rho  </V>
            <V ID="1"> rhou </V>
            <V ID="2"> rhov </V>
            <V ID="3"> rhow </V>
            <V ID="4"> E    </V>
        </VARIABLES>

        <BOUNDARYREGIONS>
            <B ID="1"> C[2] </B>
            <B ID="2"> C[3] </B>
            <B ID="3"> C[4] </B>
            <B ID="4"> C[5] </B>
            <B ID="5"> C[6] </B>
            <B ID="6"> C[7] </B>
        </BOUNDARYREGIONS>

        <BOUNDARYCONDITIONS>
            <REGION REF="1">
                <P VAR="rho"    VALUE=[2]/>
                <P VAR="rhou"   VALUE=[2]/>
                <P VAR="rhov"   VALUE=[2]/>
                <P VAR="rhow"   VALUE=[2]/>
                <P VAR="E"      VALUE=[2]/>
            </REGION>
            <REGION REF="2">
                <P VAR="rho"    VALUE=[1]/>
                <P VAR="rhou"   VALUE=[1]/>
                <P VAR="rhov"   VALUE=[1]/>
                <P VAR="rhow"   VALUE=[1]/>
                <P VAR="E"      VALUE=[1]/>
            </REGION>
            <REGION REF="3">
                <P VAR="rho"    VALUE=[4]/>
                <P VAR="rhou"   VALUE=[4]/>
                <P VAR="rhov"   VALUE=[4]/>
                <P VAR="rhow"   VALUE=[4]/>
                <P VAR="E"      VALUE=[4]/>
            </REGION>
            <REGION REF="4">
                <P VAR="rho"    VALUE=[3]/>
                <P VAR="rhou"   VALUE=[3]/>
                <P VAR="rhov"   VALUE=[3]/>
                <P VAR="rhow"   VALUE=[3]/>
                <P VAR="E"      VALUE=[3]/>
            </REGION>
            <REGION REF="5">
                <P VAR="rho"    VALUE=[6]/>
                <P VAR="rhou"   VALUE=[6]/>
                <P VAR="rhov"   VALUE=[6]/>
                <P VAR="rhow"   VALUE=[6]/>
                <P VAR="E"      VALUE=[6]/>
            </REGION>
            <REGION REF="6">
                <P VAR="rho"    VALUE=[5]/>
                <P VAR="rhou"   VALUE=[5]/>
                <P VAR="rhov"   VALUE=[5]/>
                <P VAR="rhow"   VALUE=[5]/>
                <P VAR="E"      VALUE=[5]/>
            </REGION>
        </BOUNDARYCONDITIONS>

        <!-- Initial conditions not necessary
         since they are imposed analitically -->
        <!--FUNCTION NAME="InitialConditions">
            <E VAR="rho"    VALUE="1"/>
            <E VAR="rhou"   VALUE="1"/>
            <E VAR="rhov"   VALUE="1"/>
            <E VAR="E"      VALUE="1"/>
        </FUNCTION-->

    </CONDITIONS>
</NEKTAR>

[Nektar-users] About Periodic Conditions

YU Jian