@article{wang_cheng_berndt_carlson_luo_2018, title={Application of nonlinear Krylov acceleration to a reconstructed discontinuous Galerkin method for compressible flows}, volume={163}, ISSN={["1879-0747"]}, DOI={10.1016/j.compfluid.2017.12.015}, abstractNote={A variant of Anderson Mixing, namely the Nonlinear Krylov Acceleration (NKA), is presented and implemented in a reconstructed Discontinuous Galerkin (rDG) method to solve the compressible Euler and Navier–Stokes equations on hybrid grids. A nonlinear system of equations as a result of a fully implicit temporal discretization at each time step is solved using the NKA method with a lower-upper symmetric Gauss–Seidel (LU-SGS) preconditioner. The developed NKA method is used to compute a variety of flow problems and compared with a well-known Newton-GMRES method to demonstrate the performance of the NKA method. Our numerical experiments indicate that the NKA method outperforms its Newton-GMRES counterpart for transient flow problems, and is comparable to Newton-GMRES for steady cases, and thus provides an attractive alternative to solve the system of nonlinear equations arising from the rDG approximation.}, journal={COMPUTERS & FLUIDS}, author={Wang, Chuanjin and Cheng, Jian and Berndt, Markus and Carlson, Neil N. and Luo, Hong}, year={2018}, month={Feb}, pages={32–49} }
 @article{xia_wang_luo_christon_bakosi_2016, title={Assessment of a hybrid finite element and finite volume code for turbulent incompressible flows}, volume={307}, ISSN={["1090-2716"]}, DOI={10.1016/j.jcp.2015.12.022}, abstractNote={Hydra-TH is a hybrid finite-element/finite-volume incompressible/low-Mach flow simulation code based on the Hydra multiphysics toolkit being developed and used for thermal-hydraulics applications. In the present work, a suite of verification and validation (V&V) test problems for Hydra-TH was defined to meet the design requirements of the Consortium for Advanced Simulation of Light Water Reactors (CASL). The intent for this test problem suite is to provide baseline comparison data that demonstrates the performance of the Hydra-TH solution methods. The simulation problems vary in complexity from laminar to turbulent flows. A set of RANS and LES turbulence models were used in the simulation of four classical test problems. Numerical results obtained by Hydra-TH agreed well with either the available analytical solution or experimental data, indicating the verified and validated implementation of these turbulence models in Hydra-TH. Where possible, some form of solution verification has been attempted to identify sensitivities in the solution methods, and suggest best practices when using the Hydra-TH code.}, journal={JOURNAL OF COMPUTATIONAL PHYSICS}, author={Xia, Yidong and Wang, Chuanjin and Luo, Hong and Christon, Mark and Bakosi, Jozsef}, year={2016}, month={Feb}, pages={653–669} }