Tips & Tricks

Radiation from ribbed plates
There are here two competing phenomena in the structural-acoustic behavior of bare plates versus ribbed plates:
Emna Ben Ali Vibro-Acoustics

Why would one want to use the Efimtsov model instead of the Cockburn/Robertson model for a TBL source?
From Graham: the main advantage of the Efimtsov versus the Cockburn/Robertson model is that it accounts for the dependence of the decay coefficients (i.e. correlation length) on boundary layer thickness.
Emna Ben Ali Vibro-Acoustics

Can VA One import FE NASTRAN models with superelements defined?
VA One can import FE models with superelements (SE) defined...
Emna Ben Ali Vibro-Acoustics

Does VA One SEA use cached data when solving in batch mode?
Does VA One SEA use cached data when solving in batch mode?, Yes, with a .va1 as input to the batch solve, VA One SEA will use the CLF's cached in that .va1 if they exist.
Emna Ben Ali Vibro-Acoustics

Negative Pin into a BEM fluid
I see negative Pin into a BEM fluid - what may be the reason?,This was a known issue for cases with heavy fluids
Emna Ben Ali Vibro-Acoustics

MUMPS error when solving my SEA model
I'm getting a MUMPS error when solving my SEA model - what may be the cause?, Reason for this is un-allowed or un-physical combination of physical properties in some NCTs. Correct those and the solve should go through.
Emna Ben Ali Vibro-Acoustics

Why PEM disappears when solving for coupled modes ?
PEM subsystems are nodal, whereas acoustic and structural ss are modal. The PEM ss adds to the global dynamic stiffness matrix, just as any SEA etc objects; so the PEM ss is taken into account when solving for the coupled mode. But one won't be able to visualize any modes, as there is no modal data for PEM ss, (same in coupled/uncoupled modes).
Emna Ben Ali Vibro-Acoustics

What is <Sqq> ?
is an exact expression for the ensemble average response of a system of coupled subsystems with uncertain boundaries...
Emna Ben Ali Vibro-Acoustics

Difference between using a cavity constraint vs. a Diffuse Acoustic Field source
If I apply a Diffuse Acoustic Field (DAF) source on a panel instead of constraining the pressure in an adjacent cavity, will I obtain the same results?, The results from the DAF and the constrained cavity are almost identical. The two main differences between the results will be a 3 dB offset and the fill factor effect
Emna Ben Ali Vibro-Acoustics

What is a stiffness multiplier in SEA?
Essentially it’s about adjusting the Young’s modulus to fit modes in band.
Emna Ben Ali Vibro-Acoustics