Index-Aware MOR for Gas Transport Networks

We extend the index-aware model order reduction method (IMOR) to differential-algebraic equations (DAEs) arising from gas transport networks, which have a tractability index of one or two. Applying model order reduction (MOR) techniques to DAEs has to be done carefully and the techniques, in particular for nonlinear systems, can not handle arbitrary models. In previous work, MOR for DAEs arising from gas transport networks was done by rewriting DAEs into ordinary differential equations (ODEs) by index reduction. Then, standard MOR techniques could be applied. We propose an approach to create an ODE system and algebraic equations from the original DAE, which is done automatically. That means we can get a new decoupled system easily, even if we change the discretization scheme or the coupling condition in the gas network. We explain the details of the automatic decoupling for the linearized gas transport equation and show its efficiency on several numerical examples.