1. But

Define a turbulent excitation spectrum. Different types of spectra are available:

• for « cross-flow tube bundles », « correlation length » spectra,

• for established uniform flows, parallel to circular plane or cylindrical structures, boundary layer turbulence spectra,

• excitation spectrum defined by its decomposition over a family of shape functions by providing an interspectral matrix and a list of associated shape functions. The tabl_intsp and function concepts must then be generated beforehand,

• predefined turbulence spectrum, identified on model GRAPPE1 or GRAPPE2,

• excitation spectrum associated with one or more specific forces and moments by providing an interspectral matrix of excitations (concept tabl_intsp to be generated beforehand), the list of nodes for applying these excitations, the nature of the excitation applied in each of these nodes (force or moment) and the directions of application of the excitations thus defined.

• excitation spectrum defined by a set of complex analytical functions.

Produces a spectrum-like concept.