Access Restriction

Author Smedt, Bert De ♦ Pattyn, Frank ♦ Groen, Pieter De
Source CiteSeerX
Content type Text
File Format PDF
Subject Domain (in DDC) Computer science, information & general works ♦ Data processing & computer science
Subject Keyword Velocity Field ♦ Picard Iteration ♦ Higher-order Ice-flow Model ♦ Unstable Manifold Correction ♦ Higher-order Model ♦ Original Umc Algorithm ♦ Higher-order Model Implementation ♦ Main Problem ♦ Real Data ♦ Laminar-flow Experiment ♦ Fast Solution ♦ Proper Implementation ♦ Original Algorithm ♦ True Picard Iteration ♦ Simple Relaxed Picard Algorithm
Abstract ABSTRACT. We address the usefulness of the unstable manifold correction (UMC) in a Picard iteration for the solution of the velocity field in higher-order ice-flow models. We explain under- and overshooting and how one can remedy them. We then discuss the rationale behind the UMC, initially developed to remedy overshooting, and how it was previously introduced in a Picard iteration to calculate the velocity field in higher-order models. Using a laminar-flow experiment with two higher-order model implementations, we demonstrate that it is not overshooting, but undershooting, that is the main problem when using a proper implementation for the calculation of the velocity field in higher-order models. We also consider a variant of the original UMC algorithm that often enables a relatively fast solution, but is theoretically less sound. Therefore, neither the variant nor the original algorithm is suited for these problems. We present a more appropriate, stable and simple relaxed Picard algorithm and demonstrate that, compared to the true Picard iteration and the variant of the original UMC algorithm, it results in a faster solution of the velocity field in higher-order models for problems with real data.
Educational Role Student ♦ Teacher
Age Range above 22 year
Educational Use Research
Education Level UG and PG ♦ Career/Technical Study
Learning Resource Type Article