NASTRAN hydroelastic modal studies. Volume 3: NASTRAN 3D hydroelastic analysis and MESHGEN user's manuals
Abstract
The method used to formulate the fluid/structure equations is described in the updates to the NASTRAN Theoretical Manual. The basis for defining the fluid are three dimensional finite elements connected to fluid grid points defining the Eulerian pressure at a point fixed in space. The use of a pressure single degree of freedom at each point rather than three displacements allows a finer mesh of elements with a reasonable matrix order. In the formulation of the fluid/structure system the interior fluid degrees of freedom are transformed and removed from the solution matrices. The eigenvalues of the combination are extracted from small, fully dense, symmetric mass and stiffness matrices, efficiently processed with the Givens method. The solution matrices are defined by the free surface displacements and the reduced structure coordinates.
 Publication:

Final Report Universal Analytics
 Pub Date:
 May 1977
 Bibcode:
 1977uai..reptS.....
 Keywords:

 Hydroelasticity;
 Nastran;
 Structural Analysis;
 Tanks (Containers);
 User Manuals (Computer Programs);
 Compressible Fluids;
 Computer Programs;
 External Tanks;
 Space Shuttles;
 Fluid Mechanics and Heat Transfer