[Nek5000-users] linear stability tool

Sat Mar 26 21:45:06 CDT 2016

Hi Adam,

I am guessing I am using your code for stability tools in NEK. I have
downloaded the code from https://nek5000.mcs.anl.gov/toolboxes/.

I am trying to reproduce the ext_cyl example, as is, to get some
familiarity.

I have been able to compile the code (after some modifications to compile
on the platform I intent to run my analysis). I have the base flow file
"ext_cyl0.f00005" in the simulation folder. When I run the ext_cyl, I get
the following error:

******************************************************************************************************************
call userchk
 ARNOLDI:
 Reading checkpoint
       0       0 OPEN: ARPext_cyl0.f00005
ARPext_cyl0.f00005
byte_read() :: fopen failure2!
 ERROR: mfi_arnp, wrong header; abort.

call exitt: dying ...
******************************************************************************************************************

I have also pasted below  the parameters printed in the log file for your
reference.

******************************************************************************************************************
122   Parameters from
file:/global/u2/r/rtumkur/eig_Setup/ARNOLDI/ext_cyl.rea
   1      1.00000     p001 DENSITY
   2     -50.0000     p002 VISCOS
   7      1.00000     p007 RHOCP
   8      1.00000     p008 CONDUCT
  11      50003.0     p011 NSTEPS
  12    -5.000000E-03 p012 DT
  15      2500.00     p015 IOSTEP
  17      1.00000     p017
  18     0.500000E-01 p018 GRID < 0 --> # cells on screen
  19     -1.00000     p019 INTYPE
  20      7.00000     p020 NORDER
  21     0.100000E-09 p021 DIVERGENCE
  22     0.100000E-09 p022 HELMHOLTZ
  24     0.100000E-09 p024 TOLREL
  25     0.100000E-04 p025 TOLABS
  26      1.00000     p026 COURANT/NTAU
  27      3.00000     p027 TORDER
  28      0.00000     p028 TORDER: mesh velocity (0: p28=p27)
  31      -1.00000     p031 NPERT: #perturbation modes
  59      0.00000     p059 !=0 --> full Jac. eval. for each el.
  65      1.00000     p065 #iofiles (eg, 0 or 64); <0 --> sep. dirs
  66      4.00000     p066 output : <0=ascii, else binary
  67      4.00000     p067 restart: <0=ascii, else binary
  69      1.00000     p069 : PROPER RESTART: 0 - do not use
my_full_restart; 1- use it
  71      5.00000     p071 : ARNOLDI: checkpoint file number for restart
(reading)
  72      6.00000     p072 : ARNOLDI: checkpoint file number for saving data
  99      3.00000     p099 dealiasing: <0--> off/3--> old/4--> new
 102      1.00000     p102 Dump out divergence at each time step
 108      1.00000     p108 : ARNOLDI: 0 if no arnoldi
 109      40.0000     p109 : ARNOLDI: frequency of calling arn_solve
 110      4.00000     p110 : ARNOLDI: maximal number of arnoldi cycles
 111      90.0000     p111 : ARNOLDI: size of Krylov space
 112      30.0000     p112 : ARNOLDI: number of eigenvectors
 113      1.00000E-06 p113 : ARNOLDI: arpack tolerance
 119      1.00000     p119 : SPONGE STRENGTH
 120      25.0000     p120 : SPONGE TOTAL WIDTH
 121      3.00000     p121 : SPONGE DROP WIDTH (INFLOW)
 122      5.00000     p122 : SPONGE RISE WIDTH (OUTFLOW)
******************************************************************************************************************

I'd appreciate if you can let me what am I missing in the set up which
might be leading to this issue? Please let me know if you need any other
information to understand this issue.

Regards,
Ravi

On Tue, Mar 15, 2016 at 4:06 AM, <nek5000-users at lists.mcs.anl.gov> wrote:

> Hi
>
> To force base flow to be constant you have to set negative param(31) in
> your ###.rea file. Something like
>    -1.00000     p031 NPERT: #perturbation modes
> Of course you need the base flow as well. It could be analytical one set
> in useric, or just a field read during initialisation.
> Regards
> Adam
>
>
>
> On 2016-03-15 08:49, nek5000-users at lists.mcs.anl.gov wrote:
>
>> Hi Neks,
>>
>> I'm trying to use the linear stability tool of Nek5000.
>>
>> To start with, I am trying to run the ext_cyl example. However, I have
>> found the following problem:
>>
>> ERROR: arnoldi assumes constant base flow.
>>
>> I have found on the README tutorial that the base flow has to be
>> specified on the .rea file. I have included a file in the PRESOLVE/RESTART
>> option, however I still have the same error.
>>
>> What should I modify?
>>
>> Finally, I have also used a subroutine defined in the .usr file that
>> reads the file containing the base flow. However, the error persist...
>>
>> Could you help me, please?
>>
>> Cheers
>> SL
>> _______________________________________________
>> Nek5000-users mailing list
>> Nek5000-users at lists.mcs.anl.gov
>> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
>>
>
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>

-- 
Ravi Kumar R. Tumkur, PhD.
Phone: 217 778 7538
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