Centroid of 3D element

Unknown
Unknown
edited July 2022 in Community Q&A

Hi experts,

I want to extract the centroid of 3D elements in mesh. I found this one:

https://2022.help.altair.com/2022/hwcfdsolvers/acusolve/topics/acusolve/udfgetelmcrd_acusolve_udf.htm

But, I didn't find a routine for extracting centroid. Do you think it is doable in acuSolve?

Thanks.

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Best Answer

  • acupro
    acupro
    Altair Employee
    edited July 2022 Answer ✓
    Prabin Pradhananga_20428 said:

    Also, I want to know why every element routine in acuSolve, unlike Fluent UDF, is calculated at quadrature point and not at the centroid?

    And, the routine https://2022.help.altair.com/2022/hwcfdsolvers/acusolve/topics/acusolve/udfgetelmcrd_acusolve_udf.htm

    returns how many quadrature points for hexa element? I could not distinguish between the coordinates of the quadrature point.

    AcuSolve is a node-based code, based on the Galerkin Least Squares Finite Element method, and thus doesn't really use the cell center/centroid like many Finite Volume codes do.

    Nothing in-built for making use of the centroid.  You may be able to extract cell data from the AcuSolve results in ParaView, but there's not much possible from the AcuSolve side.

Answers

  • acupro
    acupro
    Altair Employee
    edited July 2022

    You would probably need to use the nodes of the element from that function call to calculate the centroid yourself within the UDF. There is nothing pre-built to calculate the centroid.

  • Unknown
    Unknown
    edited July 2022
    acupro_21778 said:

    You would probably need to use the nodes of the element from that function call to calculate the centroid yourself within the UDF. There is nothing pre-built to calculate the centroid.

    Thanks for letting me know.

    Furthermore, I want to know whether acuSolve has UDF routine to calculate the velocity at the centroid of the element or not. I found this one:

    https://2022.help.altair.com/2022/hwcfdsolvers/acusolve/topics/acusolve/udfgetelmdata_acusolve_udf.htm

    Does that mean the velocity, pressure, temperature, etc. obtained using udfGetElmData() does not correspond to the centroid but to the quadrature point?

    If I want to extract velocity, temperature, pressure, etc. of element at centroid, then how to do it?

     

  • Unknown
    Unknown
    edited July 2022
    Prabin Pradhananga_20428 said:

    Thanks for letting me know.

    Furthermore, I want to know whether acuSolve has UDF routine to calculate the velocity at the centroid of the element or not. I found this one:

    https://2022.help.altair.com/2022/hwcfdsolvers/acusolve/topics/acusolve/udfgetelmdata_acusolve_udf.htm

    Does that mean the velocity, pressure, temperature, etc. obtained using udfGetElmData() does not correspond to the centroid but to the quadrature point?

    If I want to extract velocity, temperature, pressure, etc. of element at centroid, then how to do it?

     

    Also, I want to know why every element routine in acuSolve, unlike Fluent UDF, is calculated at quadrature point and not at the centroid?

    And, the routine https://2022.help.altair.com/2022/hwcfdsolvers/acusolve/topics/acusolve/udfgetelmcrd_acusolve_udf.htm

    returns how many quadrature points for hexa element? I could not distinguish between the coordinates of the quadrature point.

  • acupro
    acupro
    Altair Employee
    edited July 2022 Answer ✓
    Prabin Pradhananga_20428 said:

    Also, I want to know why every element routine in acuSolve, unlike Fluent UDF, is calculated at quadrature point and not at the centroid?

    And, the routine https://2022.help.altair.com/2022/hwcfdsolvers/acusolve/topics/acusolve/udfgetelmcrd_acusolve_udf.htm

    returns how many quadrature points for hexa element? I could not distinguish between the coordinates of the quadrature point.

    AcuSolve is a node-based code, based on the Galerkin Least Squares Finite Element method, and thus doesn't really use the cell center/centroid like many Finite Volume codes do.

    Nothing in-built for making use of the centroid.  You may be able to extract cell data from the AcuSolve results in ParaView, but there's not much possible from the AcuSolve side.

  • Unknown
    Unknown
    edited July 2022
    acupro_21778 said:

    AcuSolve is a node-based code, based on the Galerkin Least Squares Finite Element method, and thus doesn't really use the cell center/centroid like many Finite Volume codes do.

    Nothing in-built for making use of the centroid.  You may be able to extract cell data from the AcuSolve results in ParaView, but there's not much possible from the AcuSolve side.

    Thanks for letting me know.

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