On uncoupling structurefluid interaction problems; status report on the IDCA
Abstract
A concerted effort has been made to analyze submerged structures under explosive loadings, by utilizing the Doubly Asymptotic Approximation (DAA), to account for the structurefluid interaction. The current implementation of the DAA employs a modal analysis for the structure and a set of orthogonal functions (surface expansion functions) for the fluid, the latter being used to improve the conditioning of the governing response equations. The DAA yields exact results for high and low frequencies and produces a smooth transition between these limits. Since a more accurate fit at intermediate frequencies may prove to be important in some problems of interest, the DAA may prove to be inadequate in some cases. The InertialDamping Collocation Approximation (IDCA), gives exact results for low, high, and selected intermediate frequencies, and as such represents a potential improvement over the DAA.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 May 1977
 Bibcode:
 1977STIN...7811345B
 Keywords:

 Loads (Forces);
 Underwater Explosions;
 Underwater Structures;
 Curve Fitting;
 Damping;
 Mathematical Models;
 Vulnerability;
 Fluid Mechanics and Heat Transfer