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July 2019

12 participants
12 discussions

How to get variable value at a fixed point at every time step when the mesh is moving
by Song Xiang 06 Jul '19

06 Jul '19

Dear all, I would like to get variable value at a fixed point in physical space at every time step. Its coordinates are given as "HistoryPoints". However, my domain is moving and i need find the fixed point in the new mesh at every time step. So, I use the "UpdateGeometry()" in "Deform.cpp" to update mesh at every time step and then use "FillBoundingBoxTree()" in "MeshGraph.cpp" to update rtree so that i can find the id of element the fixed point locating in. However, the "FillBoundingBoxTree()" can not update m_boundingBoxTree according the new mesh and i always get the id of element the fixed point locating in initial mesh. Whether do i need to modify something other? Who can give some suggestions about how to get value at a fixed point in physical space at every time step when the mesh is moving? Thank you very much! Best, Song

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3DH1D History points
by Guillermo 05 Jul '19

05 Jul '19

Dear all, I am conducting a quasi 3D simulation, being the z-axis the homogeneous direction, with an homogeneous length equal to 0.1 (LZ=0.1) and up to 3 Fourier modes (HomModesZ = 4). I am interested on placing some history points along the homogeneous direction, however I am facing several issues which I would like to clarify. - First of all, I have made several tests and it seems that it is not possible to parametrize the points coordinates. I mean, the coordinates do not accept parameters defined on the parameters XML element. The following example does not provide any output result: <PARAM NAME="Points"> 0.0 LZ 0.0 </PARAM> Is there any way to parametrize the coordinates? since it will be very beneficial. - I would like to place probes at LZ/4, LZ/2 and 3*LZ/4, thus I defined the HistoryPoints filter as follows: <PARAM NAME="Points"> 0.0 0.0 0.025 0.0 0.0 0.05 0.0 0.0 0.075 </PARAM> However, I obtain the following 'error' message: Reseting History point from z = 0.075 to z = 0.05. As not Fourier interpolation is required, why do I get this error? - At the FilterHistoryPoints.cpp file I see that it is possible to specify the plane on which to evaluate the history point by using the "OutputPlane" tag. Since I could not find any example, I would like to know how to use this tag, more in precise, how to define the z-coordinate of the points along with the output plane. Is the following example correct? <FILTER TYPE="HistoryPoints"> <PARAM NAME="OutputFile">TimeValues</PARAM> <PARAM NAME="OutputFrequency">10</PARAM> <PARAM NAME="OutputPlane">0,1,2,3</PARAM> <PARAM NAME="Points"> 1 0.5 0 1 0.5 0 1 0.5 0 1 0.5 0 </PARAM> </FILTER> I expect to obtain the measurements at the coordinates (1,0.5,0),(1,0.5,0.025),(1,0.5,0.5),(1,0.5,0.075). - Also at the FilterHistoryPoints.cpp file I have seen that there is another tag, called "WaveSpace". If I implement it, will I obtain the Fourier coefficients on these points? It is somehow confusing to me, so I please you to bring some light into it, and how to use this field. I am using nektar 4.3.3 version and running in parallel with 8 cores. Let me know if you require any other information. With best regards, Guillermo

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