Operands
=========


Keyword VITE_FLUI
-----------------


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 ◊ VITE_FLUI

Keyword factor that defines the range of fluid velocities studied and the discretization.


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 ◊ VITE_MIN = vi

First speed value for which the coupling parameters are calculated.


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 ◊ VITE_MAX = vm

The last speed value for which the coupling parameters are calculated.


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 ◊ NB_POIN = NP

Define the number of speed points (the discretization step is constant).


Keyword BASE_MODALE
-------------------


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    ♦ BASE_MODALE

Keyword factor that defines the modal basis of the mode_meca concept for which the coupling parameters are calculated. Coupling changes the natural frequencies and the values of the reduced damping terms associated with each mode (keyword AMOR_REDUIT or AMOR_UNIF).


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    ♦ MODE_MECA = fashion

Modal basis for the mode_meca concept type.


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    ◊ NUME_ORDRE = l_nuor

Allows you to select the modes of the modal base of the mode_meca type to be taken into account for the calculation of the coupling.


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    ◊/AMOR_REDUIT = l_amor

List of reduced depreciations (percentage of critical depreciation) corresponding to each mode of the structure.

**Note:**

*They must be the same number as the number of modes taken into account (these modes are defined by the keyword* *NUME_ORDRE) .*


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    /AMOR_UNIF = love

The same reduced damping is applied to all the modes of the modal base.


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    ◊ AMOR_REDUIT_CONN = l_amor_c

List of reduced depreciations (percentage of critical depreciation) corresponding to each mode of the structure for the Connors method (see [R4.07.04]). According to this reference documentation, two Connors instability ratio values are provided (including one called "All Components").

**Note:**

*As for the keyword* *AMOR_REDUIT, they must be the same number as the number of modes taken into account.*


Keyword TYPE_FLUI_STRU
----------------------


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    ♦ TYPE_FLUI_STRU = typeflui

Type_flui_stru type concept. It makes it possible to define the configuration studied, that is to say the coupling coefficients used for modeling fluid-elastic forces.

**Note:**

*In the case of a configuration of the "bundle of tubes under axial flow" type (keyword factor* FAISCEAU_AXIAL *), the calculation of the coupling parameters of the structure with the fluid in a state of rest is taken into account. This calculation is made* *regardless of the fluid speed range that the user has entered with the keyword* VITE_FLUI *.*

*In this case of a fluid at rest, the transfer matrix representing the fluid-elastic force exerted on the structure takes the form of an added damping matrix.*


Keyword IMPRESSION
------------------


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    ◊ IMPRESSION

Keyword factor allowing the user to choose what information they want to have written in the RESULTAT file.


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    ◊ PARA_COUPLAGE = 'OUI' or 'NON'

With this keyword, the user can request the printing of result tables giving, for each mode, the changes in reduced speed, frequency and reduced modal damping as a function of the fluid flow speed. The value by default is' OUI '.


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    ◊ DEFORMEE = 'OUI' or 'NON'

With this keyword the user can request the printing in 'RESULTAT' format of the displacement fields corresponding to the modal deformations. The value by default is' NON '.


Operand STOP_ERREUR
--------------------


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    ◊ STOP_ERREUR = stop

Keyword that allows you to define the behavior of the code in the event of a convergence problem in the calculation of coupling coefficients for a given speed and a mode of deformation of the structure.

If STOP_ERREUR =' OUI ', the code stops with a fatal error in the event of a convergence problem by notifying the user of the speed concerned.

If STOP_ERREUR =' NON ', the code emits an alarm notifying the user of the convergence problem (speed and mode number) and stores the last value calculated for the coupling coefficients.