4. notes

In the case of a « bundle of tubes under transverse flow » configuration, it is possible to define several zones of interaction between the fluid and the structure, each of these zones being able to be modelled independently of the others. The calculation of the modal parameters of the structure subjected to a flow then takes into account each of these zones, defined explicitly in the command DEFI_FLUI_STRU [U4.25.01].

The concept produced by CALC_FLUI_STRU contains, in table form, the mass, damping and stiffness matrices for each fluid speed. The table, representing the modified modal base, can be retrieved by RECU_TABLE in order to be injected into a DYNA_TRAN_MODAL calculation. This calculation sequence is implemented in test case SDLL118A.