[Nek5000-users] Error Hmholtz VELZ

[nek5000-users at lists.mcs.anl.gov]

Dear Neks expert,
I have met one question regarding convergence process. I have set 20 elements along the flow direction (z direction) within 18 dimensionless length and Errors in Hmholtz VELZ always occur as showing below in some steps. 


Step   6568, t= 1.1221628E+02, DT= 4.1878394E-03, C=  2.974 1.4417E+05 1.6334E+01
             Solving for fluid
       6568  Project PRES           5.1352E-02   3.3155E-01   6.4564E+00  13  13
       6568  PRES gmres       332   9.9894E-05   1.9371E-03   1.0000E-04   1.5201E+01   2.0723E+01    F
       6568  Hmholtz VELX      91   9.5154E-08   1.0497E+00   1.0000E-07
       6568  Hmholtz VELY      92   9.6725E-08   1.0499E+00   1.0000E-07
       6568  Hmholtz VELZ      94   9.2542E-08   1.3732E+00   1.0000E-07
       6568  PRES gmres         1   5.5415E-15   7.3896E-15   1.0000E-04   4.4999E-02   6.6809E-02    F
       6568  Hmholtz VELX       1   5.1837E-16   1.2080E-15   1.0000E-07
       6568  Hmholtz VELY       1   5.1303E-16   1.2067E-15   1.0000E-07
       6568  Error Hmholtz VELZ     100   6.5337E-07   9.9994E-01   1.0000E-07
       6568  volflow Z              1.4895E-02   1.3403E-03   3.9043E+01   3.9044E+01
             L1/L2 DIV(V)           1.6323E-16   9.7802E-02
             L1/L2 QTL              0.0000E+00   0.0000E+00
             L1/L2 DIV(V)-QTL       1.6323E-16   9.7802E-02
       6568  Fluid done  1.1222E+02  2.5913E+01
 dump history points
   1.1222E+02   1.0000E+00   1.1906E-02 monitor


Could you please lead me the way to avoid this problem? Should I refine the mesh in z direction according to some criteria?
Thank you so much for your kindly help.


Haoran


--

鞠浩然
西安交通大学 能动学院 核科学与技术系
陕西省西安市咸宁西路28号 邮编：710049
JU Haoran
Department of Nuclear Science and Technology, School of Energy and Power Engineering,
Xi'an Jiaotong University, 710049.
No.28 Xianning West Road, Xi'an, Shanxi Province, China.
Email: juhaoran012 at 163.com
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