big structure in FEKO and CST

[J.C.Maxwell]

hi all.

I have a question about simulation in FEKO.
I want to simulate an airplane with FEKO and CST to measure the effect of the airplane body on the radiation pattern of a spiral antenna in 3GHz frequency. I do meshing and all of parameters are valid.
I tried to use MLFMM method in feko to solve, but it doesn't show any convergence. and finally simulation stops after about an hour and passing 100 iteration (defined myself). I tried this in CST too, but it need too much RAM space.
would you please help me in solving the problem or suggesting any better method.

Im using a PC with core i5 3.7GHz cpu, and 24GB of RAM.

thank you very much.

 

[sim4me]

I am not too familiar with CST. Regarding FEKO, which version are you using? Recently there has been improvements on their MLFMM solver that uses out-of-core solutions, so you can solve bigger models in effect without having to give up some on convergence. Have you read through the Help Centre pages on how to improve MLFMM convergence? (I suppose if your FEKO license is old and you didn't renew you wouldn't have access... There are some good tips there.)

Maybe consider using domain decomposition to solve the model. Else if it is a printed spiral (with dielectrics) the FEM/MLFMM solver will work much better than the default one.
Their tech support could also have some helpful tips. There are many solvers in FEKO and it is sometimes difficult to choose the "right" one.

 

[J.C.Maxwell]

I am using FEKO 5.5 full licence. when i run feko this error occurs :
"Calculate the electric near field
(NearField1)
Calculate the magnetic near field
(NearField1)
The following message from the server process (MYID= 2):
MPI error code 68224526 for process 2 of 4 (PID: 4412):
Message truncated, error stack:
MPI_Bcast(1080)...................: MPI_Bcast(buf=0x00000001423DA430, count=1, dtype=USER, root=0, MPI_COMM_WORLD) failed
MPIR_Bcast(288)...................:
MPIDI_CH3U_Post_data_receive(1625): Message from rank 0 and tag 2 truncated; 1556940 bytes received but buffer size is 29196
ERROR 33052: Internal FEKO error. Please notify the FEKO support team and provide the error number, preferably together with the FEKO input and output files.
See also message in the output file wing.out
The following message from the server process (MYID= 1):
MPI error code 68224526 for process 1 of 4 (PID: 4912):
Message truncated, error stack:
MPI_Bcast(1080)...................: MPI_Bcast(buf=0x00000001423DA430, count=1, dtype=USER, root=0, MPI_COMM_WORLD) failed
MPIR_Bcast(288)...................:
MPIDI_CH3U_Post_data_receive(1625): Message from rank 0 and tag 2 truncated; 1556940 bytes received but buffer size is 29196
ERROR 33052: Internal FEKO error. Please notify the FEKO support team and provide the error number, preferably together with the FEKO input and output files.
See also message in the output file wing.out
mpiexec aborting job...
op_read error on parent context: generic socket failure, error stack:
MPIDU_Sock_wait(2815): The specified network name is no longer available. (errno 64)
unable to read the cmd header on the parent context, generic socket failure, error stack:
MPIDU_Sock_wait(2815): The specified network name is no longer available. (errno 64).
connection to my parent broken, aborting. "

every thing looks fine but this error occurs.
I think i should change the solution method. like combining the MOM PO MLFMM and FEM. but i dont know how.

 

[sim4me]

I remember getting that error a few years ago. The tech team told me to update my FEKO and the problem went away.

 

[J.C.Maxwell]

you mean upgrade to newer version of FEKO? or upgrade feko 5.5 itself?

 

[sim4me]

I don't remember, sorreee! :sad:

 

[J.C.Maxwell]

thank you sim4me.
best regards