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Advanced Capabilities in GOMA 6.0 - Augmenting Conditions Automatic Continuation and Linear Stability Analysis

Schunk, Randy; Labreche, Duane A.; Hopkins, Matthew M.; Sun, Amy C.; Wilkes, Ed W.

This document describes the form and use of three supplemental capabilities added to Goma during 1998 -- augmenting conditions, automatic continuation and linear stability analysis. Augmenting conditions allow the addition of constraints and auxiliary conditions which describe the relationship between unknowns, boundary conditions, material properties and post-processing extracted quantities. Automatic continuation refers to a family of algorithms (zeroth and first order here, single and multi-parameter) that allow tracking steady-state solution paths as material parameters or boundary conditions are varied. The stability analysis capability in Goma uses the method of small disturbances and superposition of normal modes to test the stability of a steady- state flow, i.e., it determines if the disturbance grows or decays in time.