2008.73: Forward and Inverse Problems in Towed Cable Hydrodynamics

2008.73: Nick Polydorides, Eskild Storteig and William Lionheart (2008) Forward and Inverse Problems in Towed Cable Hydrodynamics.

Full text available as:

PDF - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader 543 Kb

Abstract

This paper addresses the problem of reconstructing the velocities of t he ocean currents impinging on a towed streamer cable during an offshore seismic survey. This study considers a two-dimensional model describing the motion of a flexible, inextensible cable in the presence of hydrodynamic drag forces in an in compressible fluid. In the first part the forward model is introduced and then sol ved to yield the cable’s velocity, curvature and tension in the knowledge of the towing vessel motion and the hydrodynamic loads applied. In sequence, we formul ate the inverse problem of inferring the ocean current velocities from discrete samples of the cable’s shape and tension and show that this is rank deficient and ill-posed. In approaching the inverse problem a numerically stable algorithm is adopted based on generalized Tikhonov regularization, in the context of robust differentiation of discrete noisy signals. In order to demonstrate the practical performance of the scheme, some examples of ocean current reconstructions obtain ed using simulated noisy data are presented.

Download Statistics: last 4 weeks
Repository Staff Only: edit this item