r4.07.02 Modeling of turbulent excitations

Summary:

We describe the modeling of turbulent excitations available in Code_Aster and how these are taken into account in a dynamics calculation. Turbulent excitations are characterized by a spectral force density, specified using the operator DEFI_SPEC_TURB [U4.44.31]. They are taken into account in a dynamic calculation by projecting the spectrum on the modal basis of the structure whose response we want to calculate. Projection operations are performed using the PROJ_SPEC_BASE [U4. 63.14] operator.

Table of Contents

• 1. Principle of calculation
  • 1.1. Determination of a modal base of the system under flow and projection of the excitation
  • 1.2. Calculation of the response to turbulent excitation: frequency resolution
  • 1.3. Calculation of the response to turbulent excitation: temporal resolution
• 2. Turbulent excitation models applicable to wire structures
  • 2.1. General principles
  • 2.2. « Correlation length » spectra
  • 2.3. Distributed turbulent excitation model
  • 2.4. Localized turbulent excitation model
• 3. Bibliography
• 4. Description of document versions