[lalatuobu]

Hi,

When I went across the Non linear FSI tutorial, there is a residual output called RMS[R], which came from the domain RMS_RTOL

I wonder what is the meaning of this residual. Its said that is the rms residual of residual vector. What is the physical meaning of residual vector.

Specifically. When I was doing a coupled NL FSI, which is PDMS (cured silica) pillar in flow domain, I have convergence with :
+-----------------------------------------------------------------------------+
| Zone 1 (Structure) |
+-----------------------------------------------------------------------------+
| Inner_Iter| Load[%]| rms[U]| rms[R]| rms[E]| VonMises|
+-----------------------------------------------------------------------------+
| 0| 100.00%| -10.895416| -3.815428| -19.498174| 4.1464e+00|
| 1| 100.00%| -10.930047| -3.815428| -19.588986| 4.1464e+00|
| 2| 100.00%| -11.084515| -3.815428| -19.884196| 4.1464e+00|
| 3| 100.00%| -10.874983| -3.815428| -19.625737| 4.1464e+00|
| 4| 100.00%| -9.117042| -3.815428| -16.155978| 4.1464e+00|
| 5| 100.00%| -9.751613| -3.815430| -17.464259| 4.1464e+00|

Which has very poor RMS R. I wonder what causes the problem and how can I improve that

[pcg]

Hi,

The physical meaning of the residual for nonlinear elasticity is nodal force imbalance.
You need to look at it against its initial norm, not against the other two metrics.

[lalatuobu]

Originally Posted by pcg

Hi,

The physical meaning of the residual for nonlinear elasticity is nodal force imbalance.
You need to look at it against its initial norm, not against the other two metrics.

Thank you!