# F_NNODE returns double number of nodes

 Register Blogs Members List Search Today's Posts Mark Forums Read

March 8, 2014, 07:58
F_NNODE returns double number of nodes
#1
New Member

David
Join Date: Jan 2014
Posts: 1
Rep Power: 0
Hello, I have done a UDF for a dynamic mesh.

This UDF finds some cells in the mesh that I am 100 % sure that are part of a none structured mesh (triangular prism cells). So when the case is initialized it writes a file .txt in the work directory with the coordinates of the nodes of each face of each cell.

This is the part of the code of the UDF and is inside a begin_c_loop:
Quote:
 c_face_loop(cells, thread_cells, n) { f2 = C_FACE(cells, thread_cells, n); numbernodes = F_NNODES(f2, thread_cells); fprintf(a, "nodes in face: %d\n", numbernodes); f_node_loop(f2, thread_cells, n2) { node2 = F_NODE(f2, thread_cells, n2); X[0] = NODE_X(node2); X[1] = NODE_Y(node2); X[2] = NODE_Z(node2); fprintf(a, "x: %1.15f y: %1.15f z: %1.15f\n", X[0], X[1], X[2]); } }
And what is written in the file for the first cell:
Quote:
 nodes in face: 6 x: -0.028009595349431 y: 0.017595577985048 z: 0.005138859618455 x: -0.028174242004752 y: 0.017617683857679 z: 0.005138888955116 x: -0.028068123385310 y: 0.017737546935678 z: 0.005138861481100 x: -0.028009733185172 y: 0.017596147954464 z: 0.006166666280478 x: -0.028174497187138 y: 0.017618408426642 z: 0.006166660226882 x: -0.028068279847503 y: 0.017738135531545 z: 0.006166667677462 nodes in face: 6 x: 0.012321649119258 y: -0.028466019779444 z: 0.002055961871520 x: 0.011974476277828 y: -0.028290204703808 z: 0.002055956050754 x: 0.012330438941717 y: -0.028029493987560 z: 0.002056002384052 x: 0.012321634218097 y: -0.028466070070863 z: 0.003083726158366 x: 0.011974455788732 y: -0.028290253132582 z: 0.003083724761382 x: 0.012330439873040 y: -0.028029559180140 z: 0.003083783434704 nodes in face: 6 x: 0.009093324653804 y: -0.024432502686977 z: 0.001027791760862 x: 0.009238600730896 y: -0.024395937100053 z: 0.001027804682963 x: 0.009149624966085 y: -0.024585215374827 z: 0.001027849735692 x: 0.009093423373997 y: -0.024432476609945 z: 0.002055566292256 x: 0.009238678030670 y: -0.024395916610956 z: 0.002055579330772 x: 0.009149681776762 y: -0.024585222825408 z: 0.002055631252006 nodes in face: 6 x: -0.027399869635701 y: 0.017587393522263 z: 0.004111350979656 x: -0.027274513617158 y: 0.017676485702395 z: 0.004111340269446 x: -0.027248876169324 y: 0.017524981871247 z: 0.004111215937883 x: -0.027399865910411 y: 0.017587494105101 z: 0.005138638429344 x: -0.027274474501610 y: 0.017676435410976 z: 0.005138631910086 x: -0.027248846367002 y: 0.017524989321828 z: 0.005138775333762 nodes in face: 6 x: -0.027567202225327 y: 0.022387191653252 z: 0.008222170174122 x: -0.027757761999965 y: 0.022486202418804 z: 0.008222165517509 x: -0.027604026719928 y: 0.022614669054747 z: 0.008222172968090 x: -0.027567058801651 y: 0.022387424483895 z: 0.009250000119209 x: -0.027757575735450 y: 0.022486483678222 z: 0.009250000119209 x: -0.027603834867477 y: 0.022614952176809 z: 0.009250000119209
There are two problems:

Why in a face are six nodes when the faces are triangular or rectangular?

And the other problem is that those faces must be two triangular and three rectangular for each cell and they aren't.

Is curious that most of the values differs a bit from another of the same face and if you plot the six points of a face you can see they are almost the same by pairs. But why this happens? I'm not understanding something right?

I have searched in the manual trying to find something that explains this but I haven't find anything.

I'm using fluent 12 in Ubuntu 13.10 and the manual is also of fluent 12.

 Tags dynamic mesh, f_nnode, problem, problems, udf

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post smnaryal CFX 9 September 17, 2017 21:07 giulio_romanelli OpenFOAM Running, Solving & CFD 48 January 15, 2016 09:20 aeroman FLUENT 4 July 1, 2015 06:09 RAJ KIRAN ANSYS Meshing & Geometry 2 January 5, 2013 16:05 payam_IUST FLUENT 1 February 13, 2012 08:06

All times are GMT -4. The time now is 15:37.