Implementation of a Harmonic Balance Solver into a Compressible CFD Code

Rapport, 2017

In this project the Harmonic Balance technique for solving time periodic problems in fluid dynamics has been implemented into the parallel Navier-Stokes solver G3D::Flow. Performance issues with regards to the original implementation are identified using two profiling tools, Cachegrind and Allinea-Map 6.11. These findings are used to derive a numerical algorithm that benefits from both improved cache locality and loop performance by utlizing blocked matrix multiplication and vectorization. The scaling properties of the Harmonic Balance technique are also demonstrated by deriving an approximate performance model and comparing it to numerical results obtained at the Triolith and Hebbe computer clusters at Linköping and Chalmers Univeristy.