Learning Forum

[imomoh]

Hi,

I am trying to run a one-way transient couple simulation using Fluent and Rocky. My journal file runs fine, and the simulation progresses. However, after the simulation, I find an empty .f2r file with only a time record at 0.0 s. This means that there is no writing done at any point other than the start of the simulation. The simulation therefore is not useful. Please can anyone tell me what is wrong? Here is a copy of my journal file:

; Start transcript

/file/start-transcript "fluent.log"

(define rocky/library-path "/opt/ansys/v242/rocky/bin/lib/") 

(ti-menu-load-string "/file/read-macros \"/opt/ansys/v242/rocky/fluent/udfs/rocky_fluent_coupling.scm\"")

/define/user-defined/compiled-functions load "/opt/ansys/v242/rocky/fluent/udfs/24.2.0/one_way_transient"

; Read the Fluent case (gzipped)

/rc FFF-4-50000_2.cas.gz

/rd FFF-4-50000_2.dat.gz

; Initialize solution

/solve/initialize/initialize-flow

/define/user-defined/execute-on-demand/"initialize_one_way_transient_data::one_way_transient"

; Set time step

; /solve/set/transient-controls/fixed-user-specified yes

/solve/set/transient-controls/time-step-size 0.001 

/solve/dual-time-iterate 60000 10 

/wc SimOneWayCase.cas.gz

/wd SimOneWayData.dat.gz

; Stop transcript

/file/stop-transcript

; Exit Fluent

/exit 

yes

After 1 minute, my .f2r time record looks like ...
"motions": [],
    "times": [
        0.0
    ],
    "version": 20220912
...

How do I correct this? This is a one-way transient simulation on HPCC. There is one error in my error log. I wonder if this is related to it. Here is the error:

Node 0: Doesn't have write permissions for /opt/ansys/v242/rocky/fluent/udfs/24.2.0/one_way_transient/lnamd64/3ddp_node. If using local disk, make sure UDF lib is synced up on all nodes.

I will be happy to recieve inputs and suggestions on how to go about this.

 

[Jackson Gomes]

Hi imomoh,

Your issue is caused by missing write permissions on the UDF library directory. Fluent cannot execute or sync the compiled UDF, which blocks the coupling routine from writing to the .f2r file. Give write permissions to the directory /opt/ansys/v242/rocky/fluent/udfs/24.2.0/one_way_transient/lnamd64 on all nodes, or use a working directory where you have full access.

[imomoh]

Hi Jackson,

 

Thank you. I moved to a working directory where I have full access. This works fine now without errors. There is one question, however. The .f2r file still does not show any records of additional time directory even without errors. Am I missing a write command in my journal file? If yea, where does it go to?

...

    ],
    "motions": [],
    "times": [
        0.0
    ],
    "version": 20220912
}