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Fatal error during Normal Mode simulation

rex.he
When I did Normal Modes simulation using MFLUID, VMOPT=2, I get below fatal error:
 
 *** USER FATAL MESSAGE 6136 (UDSFA)
   INSUFFICIENT CORE FOR NUMERIC PHASE OF SPARSE DECOMPOSITION.
   USER ACTION: INCREASE CORE BY ********** WORDS
0FATAL ERROR
1                    * * * END OF JOB * * *
 
How can I fix this?
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  • 0
    MFLUID is very memory intensive. You can try using METHOD(COUPLED)=XX in case control. This will give you comparable answer, not exactly same as MFLUID. This is there from Nastran 2020 QRG.
     
    4. METHOD(COUPLED) is only used when STRUCTURE and FLUID COUPLED problem. The
    corresponding EIGRL or EIGR requires either the frequency range of interest or ND (number of
    roots desired) entry. The real coupled modes computation is done with combination of Lanczos
    method and Subspace iteration method.
    METHOD(COUPLED) is recommended for heavy fluid (like liquids) model. When it is applied to
    the light fluid model, it might require more coupled modes to get the correct result.
     
    Just require to model the complete structure and the fluid cavity and use the METHOD(COUPLED)=XX..
    Attached Files (1)
Reply
  • 0
    MFLUID is very memory intensive. You can try using METHOD(COUPLED)=XX in case control. This will give you comparable answer, not exactly same as MFLUID. This is there from Nastran 2020 QRG.
     
    4. METHOD(COUPLED) is only used when STRUCTURE and FLUID COUPLED problem. The
    corresponding EIGRL or EIGR requires either the frequency range of interest or ND (number of
    roots desired) entry. The real coupled modes computation is done with combination of Lanczos
    method and Subspace iteration method.
    METHOD(COUPLED) is recommended for heavy fluid (like liquids) model. When it is applied to
    the light fluid model, it might require more coupled modes to get the correct result.
     
    Just require to model the complete structure and the fluid cavity and use the METHOD(COUPLED)=XX..
    Attached Files (1)
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