8.5. Frequently Asked Questions#

8.5.1. Where are my Flow360 credentials stored locally?#

Your Flow360 credentials are encrypted and stored locally (if you hit Yes previously at authentication step) at

~/.flow360/

For security, your password is stored as hashed value, so nobody can guess your password.

8.5.2. How to check my mesh processing status?#

To list all your mesh files:

>>> flow360client.mesh.ListMeshes()

To view one particular mesh:

>>> flow360client.mesh.GetMeshInfo('')

8.5.3. My case is still running, but how can I check the current residual and surface force result?#

>>> caseResid = flow360client.case.GetCaseResidual('')

8.5.4. How do I download or view a finished case result?#

To download the surface data (surface distributions and slices):

>>> flow360client.case.DownloadSurfaceResults('', '/tmp/surfaces.tar.gz')

Replace the second parameter with your target location and output file name, ending with ‘.tar.gz’.

To download the entire flowfield:

>>> flow360client.case.DownloadVolumetricResults('', '/tmp/volume.tar.gz')

8.5.5. How can I delete my mesh or case?#

To delete a mesh:

>>> flow360client.mesh.DeleteMesh('')

To delete a case:

>>> flow360client.case.DeleteCase('')

Danger

You will not be able to recover deleted meshes or cases, including results after deletion.

8.5.6. Does Flexcompute charge for data storage?#

For some data storage we do not charge, but for some data we do. See details:

resource

storage type

storage price

surface mesh

free

volume mesh

free

case

standard

0.05 FlexUnit/GB/month (or 0.00166 FlexUnit/GB/day)

archived

0.005 FlexUnit/GB/month

Warning

The minimum archive duration is 6 months (180 days). Restoring an archived case before this 6 month minimum will incur a one-time pro-rate charge for the remainder.

Example: The user runs a case on day 1, on day 10 the case is archived, and on day 13 the case is restored. The transaction history will look like this:

  • day 1 - standard charge

  • ...

  • day 9 - standard charge

  • day 10 - archived charge

  • ...

  • day 12 - archived charge

  • day 13 - one-time pro-rata charge for the remaining archive minimum duration (180 - 3 = 177 days)

  • day 13 - standard charge

  • day 14 - standard charge

  • ...

The pro-rata charge will display in transaction history as:

../../_images/archived_prorata_example.png

To reduce data storage costs we encourage users to:

  1. Delete case if results will no longer be needed

  2. Download results to local drive and delete case from Flow360

  3. Archive case to reduce storage costs by 10x and still be able to revisit the case in the future

8.5.7. What is storage type?#

We have two storage types: standard and archived. You can check storge type for each case next to the storage size on the case table view:

../../_images/standard_storage_icon.png ../../_images/archived_icon.png

Standard storage allows for all operations: retry case, fork case, download all results including surface results and volumetric results.

Archived storage disables these operations: fork case, retry direct child case, download surface and volume results.

8.5.8. How can I archive my case?#

You can only archive a case with status completed and storage type standard.

To archive an individual case follow these steps:

  1. Go to flow360.simulation.cloud/.

  2. Navigate to case you want to archive

  3. From action list click Archive button:

../../_images/archive_action.png

  1. You will see the following window with details about archiving operation:

../../_images/archive_message.png

Warning

The archiving operation is fast, but restoring can take up to 48 hours.

  1. Select “Archive”. The icon next to storage size will change:

../../_images/archiving_icon.png

  1. Archiving usually takes up to few minutes. When done, the storage type becomes archived.

8.5.9. How can I restore my archived case?#

  1. Go to flow360.simulation.cloud/.

  2. Navigate to case you want to restore

  3. From action list click Restore button:

../../_images/restore_action.png

  1. You will see the following window with details about restoring operation:

../../_images/restore_message.png

Warning

When you restore data from archive before the six month period, you will see a pro-rata charge added to your transaction history for the remaining duration.

  1. Select “Restore”. The icon next to storage size will change:

../../_images/restoring_icon.png

  1. Restoring takes up to 48 hours. When done, the storage type becomes standard.

8.5.10. I have many cases, how can I archive all of them at once?#

Contact support@flexcompute.com for assistance.

8.5.11. SolverError: Error when calculating patch interpolation coefficients. What does this mean?#

When running a case with a rotational volume zone, if you get a solver error that looks like this:

Error when calculating patch interpolation coefficients. Patch has a distance mismatch of 0.7883948e-01
with matching patch at location [1.7592032e-1, 1.0184957e-03, -4.7304816e-1].

This means that at a given time step, once the mesh has been rotated according to the prescribed motion, the maximum distance between the two interfaces is 0.7883948e-01. If this maximum distance between the two patches is greater than 20% of the maximum edge length contained in either patch, this error will be raised. It indicates that either the center of rotation/axis of rotation is likely incorrect or that the mesh is too coarse in this location.

8.5.12. What does the “VelocityRelative” mean in the volumeOutput of the case configuration?#

In a rotational domain, the absolute velocity, \(\overrightarrow{\boldsymbol{U}}_\text{absolute}\), of each fluid element could be treated as the summation of a relative velocity, \(\overrightarrow{\boldsymbol{U}}_\text{relative}\), and a velocity due to the rotating frame, \(\overrightarrow{\Omega}\times \overrightarrow{r}\). The “VelocityRelative” means the \(\overrightarrow{\boldsymbol{U}}_\text{relative}\):

(8.5.1)#\[\overrightarrow{\boldsymbol{U}}_\text{absolute} = \overrightarrow{\boldsymbol{U}}_\text{relative} + \overrightarrow{\Omega}\times \overrightarrow{r}\]

It should be noted that the above relative velocity is zero on any no-slip walls within rotational blocks.

8.5.13. How can I switch to volumeZones->referenceFrame?#

Attention

Usage of slidingInterfaces is deprecated, we highly recommend users to use volumeZones->referenceFrame for specifying rotational volume zones. The details of slidingInterfaces can be found in previous versions of the documentation.

For a simulation with rotational volume zones (named sliding interfaces previously), the two code snippets below show the legacy, using slidingInterfaces, and the new case configurations, using volumeZones->referenceFrame. Compared to the legacy case configuration, the SlidingInterface boundaries are removed in the new one. In the new configuration, volumeZones specifies that innerRotating volume zone is a rotating zone. By default, the omitted volume zones are treated as stationary fluid zones (see details), so the farField volume zone is a stationary fluid volume zone. By being aware that farField (stationary fluid volume zone) is adjacent to innerRotating (rotating fluid volume zone), Flow360 will handle the interfaces between them using the sliding interface technique. The entire slidingInterfaces section is no longer necessary in the new configuration.

Listing 8.5.1 legacy configuration about sliding interface#
{
   "boundaries" : {
       "farField/farField" : { "type" : "Freestream" },
       "farField/rotationInterface" : { "type" : "SlidingInterface" },
       "innerRotating/rotationInterface" :   { "type" : "SlidingInterface" },
       "innerRotating/blade" :   { "type" : "NoSlipWall" }
   },
   "slidingInterfaces" : [
   {
       "stationaryPatches" : ["farField/rotationInterface"],
       "rotatingPatches" : ["innerRotating/rotationInterface"],
       "axisOfRotation" : [0,0,-1],
       "centerOfRotation" : [0,0,0],
       "omega" : 1.84691e-01,
       "volumeName" : ["innerRotating"]
   }
   ]
}
Listing 8.5.2 new configuration about sliding interface#
{
   "boundaries" : {
       "farField/farField" : { "type" : "Freestream" },
       "innerRotating/blade" :   { "type" : "NoSlipWall" }
   },
   "volumeZones":{
       "innerRotating":{
           "referenceFrame":{
               "axisOfRotation" : [0,0,-1],
               "centerOfRotation" : [0,0,0],
               "omegaRadians" : 1.84691e-01
           }
       }
   }
}

Note

The volume zones, existing in the mesh but missing in the volumeZones of case configuration, are treated as stationary fluid zones in Flow360 by default, so stationary fluid zones are not required to specify in case configuration. However, Flow360 does not support simulations containing two adjacent volume zones, which are both stationary. If you want to do simulations in such a scenario, a referenceFrame with omega:0 can be assigned to either of them.

Important

The new case configuration shown in Listing 8.5.2 is applicable to cases from all meshes, regardless of whether the mesh contains ZoneGridConnectivity or not. Flow360 automatically detects multi-zone interfaces.