[Nek5000-users] An abrupt error of "unconverged Helmh3

nek5000-users at lists.mcs.anl.gov nek5000-users at lists.mcs.anl.gov
Wed Jun 7 09:09:36 CDT 2017


Hi,

Thanks for your reply.
The simulation is in a 3D box with moving meshes.
Surface waves are excited by the fluctuation of ambient pressure.
Based on my tests, the error of unconverged Helmh3 fluid seems to be related with random heat flux, which is set as
         flux = -1.0e-3
         big = 1.0e7*ix + 1.0e8*iy + 1.0e9*ieg
         random = sin(big)
         flux = flux + random*flux/10.0
The heat flux changes buoyancy, affecting fluid motions.

When the random flux is removed, the simulation runs well.

Thanks.

> On Jun 6, 2017, at 12:09 PM, nek5000-users-request at lists.mcs.anl.gov wrote:
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Tue, 6 Jun 2017 13:27:40 +0000
> From: nek5000-users at lists.mcs.anl.gov
> To: "nek5000-users at lists.mcs.anl.gov"
> 	<nek5000-users at lists.mcs.anl.gov>
> Subject: [Nek5000-users] An abrupt error of "unconverged Helmh3 fluid"
> Message-ID:
> 	<mailman.8093.1496755680.2967.nek5000-users at lists.mcs.anl.gov>
> Content-Type: text/plain; charset="us-ascii"
> 
> Dear Neks,
> 
> I am using the moving mesh to simulate surface gravity waves with some random heat flux at the surface.
> The codes ran well for a while, but it suddenly pop out an error of unconverged Helmh3 fluid, as shown in the below log file (Step 14650).
> 
> Could anyone give me a hint on this kind of error?
> 
> Thank you,
> Peng
> 
> 
> Step  14647, t= 7.3235000E+01, DT= 5.0000000E-03, C=  0.036 2.8716E+04 1.9695E+00
>             Solving for Hmholtz scalars
>      14647  Hmholtz TEMP       4   6.0654E-16   1.4699E-01   1.0000E-12
>      14647  Scalars done  7.3235E+01  3.9568E-02
>             Solving for fluid
>      14647  Helmh3 fluid       4   1.9934E-13   8.0532E-04   1.0000E-12
>      14647  U-PRES gmres      14   4.5296E-11   2.2779E-03   1.0000E-10   8.2958E-02   2.5954E-01
>      14647  Fluid done  7.3235E+01  3.7241E-01
> Step  14648, t= 7.3240000E+01, DT= 5.0000000E-03, C=  0.035 2.8718E+04 1.9642E+00
>             Solving for Hmholtz scalars
>      14648  Hmholtz TEMP       4   6.0987E-16   1.4701E-01   1.0000E-12
>      14648  Scalars done  7.3240E+01  3.9551E-02
>             Solving for fluid
>      14648  Helmh3 fluid       4   1.9904E-13   8.0535E-04   1.0000E-12
>      14648  U-PRES gmres      14   4.5647E-11   2.2779E-03   1.0000E-10   8.3140E-02   2.5985E-01
>      14648  Fluid done  7.3240E+01  3.7297E-01
> Step  14649, t= 7.3245000E+01, DT= 5.0000000E-03, C=  0.034 2.8720E+04 1.9658E+00
>             Solving for Hmholtz scalars
>      14649  Hmholtz TEMP       4   6.1309E-16   1.4704E-01   1.0000E-12
>      14649  Scalars done  7.3245E+01  3.9058E-02
>             Solving for fluid
>      14649  Helmh3 fluid       4   1.9875E-13   8.0535E-04   1.0000E-12
>      14649  U-PRES gmres      14   4.5884E-11   2.2778E-03   1.0000E-10   8.3552E-02   2.5956E-01
>      14649  Fluid done  7.3245E+01  3.7226E-01
> Step  14650, t= 7.3250000E+01, DT= 5.0000000E-03, C=  0.033 2.8722E+04 1.9614E+00
>             Solving for Hmholtz scalars
>      14650  Hmholtz TEMP       4   6.1615E-16   1.4707E-01   1.0000E-12
>      14650  Scalars done  7.3250E+01  3.9481E-02
>             Solving for fluid
> 14650   201 Unconverged Helmh3 fluid rbnorm =          NaN 0.100000E-11
>      14650  U-PRES gmres     120          NaN          NaN   1.0000E-10   7.0555E-01   2.3985E+00
>      14650  Fluid done  7.3250E+01  5.4078E+00
> Step  14651, t= 7.3255000E+01, DT= 5.0000000E-03, C=    NaN 2.8729E+04 7.0068E+00
>             Solving for Hmholtz scalars
>      14651  Error Hmholtz TEMP     200          NaN          NaN   1.0000E-12
>      14651  Scalars done  7.3255E+01  1.0293E+00
>             Solving for fluid
> 14651   201 Unconverged Helmh3 fluid rbnorm =          NaN 0.100000E-11
>      14651  U-PRES gmres     120          NaN          NaN   1.0000E-10   7.0602E-01   2.4098E+00
>      14651  Fluid done  7.3255E+01  5.3955E+00
> Step  14652, t= 7.3260000E+01, DT= 5.0000000E-03, C=    NaN 2.8738E+04 9.1272E+00
>             Solving for Hmholtz scalars
>      14652  Error Hmholtz TEMP     200          NaN          NaN   1.0000E-12
>      14652  Scalars done  7.3260E+01  1.0415E+00
>             Solving for fluid
> 14652   201 Unconverged Helmh3 fluid rbnorm =          NaN 0.100000E-11
>      14652  U-PRES gmres     120          NaN          NaN   1.0000E-10   7.0562E-01   2.3933E+00
>      14652  Fluid done  7.3260E+01  5.3900E+00
> 
> ------------------------------
> 
> Message: 2
> Date: Tue, 6 Jun 2017 13:33:50 +0000
> From: nek5000-users at lists.mcs.anl.gov
> To: "nek5000-users at lists.mcs.anl.gov"
> 	<nek5000-users at lists.mcs.anl.gov>
> Subject: Re: [Nek5000-users] An abrupt error of "unconverged Helmh3
> 	fluid"
> Message-ID:
> 	<mailman.8096.1496756053.2967.nek5000-users at lists.mcs.anl.gov>
> Content-Type: text/plain; charset="us-ascii"
> 
> Pend, 
> 
> can you please give more details on the case you are trying to run with Nek5000? How did you set up your case? Did you start from one of the examples?
> 
> Thanks.
>> On Jun 6, 2017, at 9:27 AM, nek5000-users at lists.mcs.anl.gov wrote:
>> 
>> Dear Neks,
>> 
>> I am using the moving mesh to simulate surface gravity waves with some random heat flux at the surface.
>> The codes ran well for a while, but it suddenly pop out an error of unconverged Helmh3 fluid, as shown in the below log file (Step 14650).
>> 
>> Could anyone give me a hint on this kind of error?
>> 
>> Thank you,
>> Peng
>> 
>> 
>> Step  14647, t= 7.3235000E+01, DT= 5.0000000E-03, C=  0.036 2.8716E+04 1.9695E+00
>>            Solving for Hmholtz scalars
>>     14647  Hmholtz TEMP       4   6.0654E-16   1.4699E-01   1.0000E-12
>>     14647  Scalars done  7.3235E+01  3.9568E-02
>>            Solving for fluid
>>     14647  Helmh3 fluid       4   1.9934E-13   8.0532E-04   1.0000E-12
>>     14647  U-PRES gmres      14   4.5296E-11   2.2779E-03   1.0000E-10   8.2958E-02   2.5954E-01
>>     14647  Fluid done  7.3235E+01  3.7241E-01
>> Step  14648, t= 7.3240000E+01, DT= 5.0000000E-03, C=  0.035 2.8718E+04 1.9642E+00
>>            Solving for Hmholtz scalars
>>     14648  Hmholtz TEMP       4   6.0987E-16   1.4701E-01   1.0000E-12
>>     14648  Scalars done  7.3240E+01  3.9551E-02
>>            Solving for fluid
>>     14648  Helmh3 fluid       4   1.9904E-13   8.0535E-04   1.0000E-12
>>     14648  U-PRES gmres      14   4.5647E-11   2.2779E-03   1.0000E-10   8.3140E-02   2.5985E-01
>>     14648  Fluid done  7.3240E+01  3.7297E-01
>> Step  14649, t= 7.3245000E+01, DT= 5.0000000E-03, C=  0.034 2.8720E+04 1.9658E+00
>>            Solving for Hmholtz scalars
>>     14649  Hmholtz TEMP       4   6.1309E-16   1.4704E-01   1.0000E-12
>>     14649  Scalars done  7.3245E+01  3.9058E-02
>>            Solving for fluid
>>     14649  Helmh3 fluid       4   1.9875E-13   8.0535E-04   1.0000E-12
>>     14649  U-PRES gmres      14   4.5884E-11   2.2778E-03   1.0000E-10   8.3552E-02   2.5956E-01
>>     14649  Fluid done  7.3245E+01  3.7226E-01
>> Step  14650, t= 7.3250000E+01, DT= 5.0000000E-03, C=  0.033 2.8722E+04 1.9614E+00
>>            Solving for Hmholtz scalars
>>     14650  Hmholtz TEMP       4   6.1615E-16   1.4707E-01   1.0000E-12
>>     14650  Scalars done  7.3250E+01  3.9481E-02
>>            Solving for fluid
>> 14650   201 Unconverged Helmh3 fluid rbnorm =          NaN 0.100000E-11
>>     14650  U-PRES gmres     120          NaN          NaN   1.0000E-10   7.0555E-01   2.3985E+00
>>     14650  Fluid done  7.3250E+01  5.4078E+00
>> Step  14651, t= 7.3255000E+01, DT= 5.0000000E-03, C=    NaN 2.8729E+04 7.0068E+00
>>            Solving for Hmholtz scalars
>>     14651  Error Hmholtz TEMP     200          NaN          NaN   1.0000E-12
>>     14651  Scalars done  7.3255E+01  1.0293E+00
>>            Solving for fluid
>> 14651   201 Unconverged Helmh3 fluid rbnorm =          NaN 0.100000E-11
>>     14651  U-PRES gmres     120          NaN          NaN   1.0000E-10   7.0602E-01   2.4098E+00
>>     14651  Fluid done  7.3255E+01  5.3955E+00
>> Step  14652, t= 7.3260000E+01, DT= 5.0000000E-03, C=    NaN 2.8738E+04 9.1272E+00
>>            Solving for Hmholtz scalars
>>     14652  Error Hmholtz TEMP     200          NaN          NaN   1.0000E-12
>>     14652  Scalars done  7.3260E+01  1.0415E+00
>>            Solving for fluid
>> 14652   201 Unconverged Helmh3 fluid rbnorm =          NaN 0.100000E-11
>>     14652  U-PRES gmres     120          NaN          NaN   1.0000E-10   7.0562E-01   2.3933E+00
>>     14652  Fluid done  7.3260E+01  5.3900E+00
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