Acoustics is one of the reasons that led me to trying CA. I got a pipe with different BCs to solve, and agrree with hand calcs, nice. However, I am struggling with some of the outputs, maybe someone spots what I'm doing wrong.
1.- We get the following outputs in the MED (for PV) results file:
-----------------------------------------------------------
COMPOSANTES DES CHAMPS PRESENTS DANS LE RESULTAT : 00000026
- CHAMP PRES :
* PRES
- CHAMP PRAC_NOEU :
* PRES_R
* PRES_I
* DB
-----------------------------------------------------------
It turns out that the DB (decibels) seems to be hard-wired to a Pref = 2e-05Pa; i.e. for models in meters. When I solve a model in mm, this is out, as it still uses 2e-05, instead of 2e-11MPa (0dB SPL). I read this part in help docs and examples, but I cannot find where/how to change Pref for dB field outputs.
2.- I then tried to generate the scalar output via: CALC_CHAM --> CHAM_UTIL, followed the examples in docs with this syntax:
spl = "20*log10(sqrt(PRES_R**2+PRES_I**2)) / Pref";
SPL_cal = FORMULE(
NOM_PARA = ('PRES_R', 'PRES_I'),
Pref = 2.0e-11, ### ac press reference in MPa; model in mm.
VALE = spl,
INFO = 2,
);
HARMO = CALC_CHAMP(
# GROUP_MA = 'tetra10_els',
reuse = HARMO,
RESULTAT = HARMO,
# ACOUSTIQUE = ('INTE_NOEU', 'PRAC_NOEU',),
ACOUSTIQUE = ('PRAC_NOEU',),
CHAM_UTIL = _F(
NOM_CHAM = "PRAC_NOEU",
FORMULE = SPL_cal,
NUME_CHAM_RESU = 1,
),
);
And I get this error, which no matter what I tried, can't get round it:
║ <EXCEPTION> <CHAMPS_14>
║
║ Il n'est pas possible de créer le champ 'UT01_NOEU' dans la structure
║ de donnée
║ '00000026'.
║
║ Conseil:
║ Vérifiez que le champ n'existe pas déjà.
║ Il est possible que
║ cette structure de donnée n'accepte pas ce type de champ.
3.- MED write, complex format option:
Following the 'PARTIE =' entry in help docs here, it seems to imply that we can change the format of the complex numbers output, e.g. using "REEL" or "MODULE". But it doesn't, I always get PRES_R & PRES_I. But it seems to muck up the PRES value, which I'd expect to be a MAG, always, since we already get the R & I parts...
This for the MED file, all outputs onto tables in text result file work fine, as expected.
Here is the little test model that shows the error above in DB calcs, and other points when commenting CHAM_UTIL out, so that it runs OK. mm_ahlv100k.zip
Let me know if anyone knows about any of these pls, and/or where I am being thick.
Cheers,
Jesus
