Nonlinear Harmonics Method for Supercomputer Simulations of Fluid Dynamics in Turbomachines with Higher Accuracy on Unstructured Meshes

The Non-Linear Harmonics (NLH) technology for simulation of flow in turbomachines is presented. It allows to consider unsteady effects related to blade passing frequencies of adjacent rows. The implementation of the NLH within the 2nd-order higher accuracy control-volume unstructured numerical algorithm realized in the parallel heterogeneous code NOISEtte is given. It includes description of mathematical models, boundary conditions (along with rotor-stator interface), numerical aspects, and accompanying computational techniques. Both explicit and implicit pseudo-time integration algorithms are described. Details of program realization, which follows hybrid MPI+OpenMP parallelization, are considered. The performance of the NLH is demonstrated on test cases.