Modification of the spectrum

Modification of the spectrum

Ver: 3 DESCRIPTION This menu allows the user to modify, for each mode, the value of the viscosity (mu) (or the elastic modulus (ge)) and the value of the relaxation time (lambda).

By default, the relaxation spectrum is specified by means of pairs <viscosity, relaxation time>.

OPTIONS

-3' Switch to elasticity-relaxation time data

Selecting this option allows the user to specify the relaxation spectrum by means of pairs (relaxation force - relaxation time).
Not available for shell models.

-3" Switch to viscosity-relaxation time data

Selecting this option allows the user to specify the relaxation spectrum by means of pairs (viscosity - relaxation time).
Mandatory for shell models.

-2 Number of relaxation modes (N <= 8)

Sets the number of different relaxation modes

-1 No modification

The user accepts the current values

1 Modify the whole spectrum

Allows the user to check/modify each relaxation mode sequentially.
At this level, the user can set the viscosity (or the relaxation force) and the relaxation time.
By default, all parameters values are equal to 1.

2 Modify some values of the spectrum

Allows the user to enter a sub-menu in which he can choose to modify the i-th relaxation mode.
At this level, the user can set the viscosity (or the relaxation force) and the relaxation time.
By default, all parameters values are equal to 1.

NOTES In view of the non-linearities intrinsic to viscoelastic models, a non-linear strategy must absolutely be used to reach high Weissenberg numbers.

The units for viscosity (mu), elasticity (ge) and relaxation time (lambda) are :

parameter mass length time temperature

ge 1 -1 -2 -

lambda - - 1 -

mu 1 -1 -1 -

SEE ALSO

viscoelastic fluid of the integral type (UM)
evolution (UM)
s-dependence (RM)
create a new task (RM)
system of units (RM)

-3'	Switch to elasticity-relaxation time data
	Selecting this option allows the user to specify the relaxation spectrum by means of pairs (relaxation force - relaxation time). Not available for shell models.
-3"	Switch to viscosity-relaxation time data
	Selecting this option allows the user to specify the relaxation spectrum by means of pairs (viscosity - relaxation time). Mandatory for shell models.
-2	Number of relaxation modes (N <= 8)
	Sets the number of different relaxation modes
-1	No modification
	The user accepts the current values
1	Modify the whole spectrum
	Allows the user to check/modify each relaxation mode sequentially. At this level, the user can set the viscosity (or the relaxation force) and the relaxation time. By default, all parameters values are equal to 1.
2	Modify some values of the spectrum
	Allows the user to enter a sub-menu in which he can choose to modify the i-th relaxation mode. At this level, the user can set the viscosity (or the relaxation force) and the relaxation time. By default, all parameters values are equal to 1.

`parameter`	`mass`	`length`	`time`	`temperature`
`ge`	`1`	`-1`	`-2`	`-`
`lambda`	`-`	`-`	`1`	`-`
`mu`	`1`	`-1`	`-1`	`-`