Opened 9 years ago
Last modified 9 years ago
#3883 closed task
Modelica.Fluid.Examples.Explanatory.MomentumBalanceFittings — at Version 2
| Reported by: | Volker Waurich | Owned by: | |
|---|---|---|---|
| Priority: | normal | Milestone: | Future |
| Component: | Run-time | Version: | |
| Keywords: | MSL_trunk, MSL_3.2.1 | Cc: | Willi Braun, Vitalij Ruge |
Description (last modified by )
Hi,
Just to document some debug insight.
A non-linear system does not converge during initialization.
The problem is as follow:
One residual in simcode equation 50 is computed as:
res = rightAdaptor.A_mean * rightAdaptor.dp_fg + rightAdaptor.F_p
If I set almost correct start values (according to dymola)
The numerical values for this residual are:
3.92699e+119 * -6.53663e+002 + 2.56825e+122
If you look at the mantissas, this seems to be on the right way. But I guess multiplying such a big and small number reveals some numerical issues.
Change History (2)
comment:1 by , 9 years ago
comment:2 by , 9 years ago
| Description: | modified (diff) |
|---|
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Besides that these huge numbers are generated from a function call which has kind of "regular" physical dimensional inputs. So the sensitity of this "transfer function" is quite big.