Solution verification of CTF and CTF-R using isokinetic advection test problems

This work performs a thorough code order verification study on Coolant Boiling in Rod Arrays - Three Field (COBRA-TF) and the corresponding residual version. A very simple single-channel isokinetic advection problem is used with three different inlet conditions: constant, hyperbolic tangent, and cosine. The observed order of accuracy is shown to be one for all simulations, which is consistent with the formal order of accuracy. Small variations in the observed order can be attributed to iterative error in the solution algorithm, the influence of higher-order terms, secondary effects on the pressure and velocity, or possible mistakes in the coding or verification implementation. This work is one of the first code order verification studies to be documented for the current version of CTF, which is developed at North Carolina State University in cooperation with the Consortium for Advanced Simulation of Light Water Reactors. (authors)