Ligthill’s aeroacoustic analogy applied to an automotive turbocharger compressor
* Presenting author
Abstract:
For computing CFD simulations to investigate aeroacoustics of turbocharger compressors, it is of fundamental importance to resolve turbulent structures at the location of their generation. This results in high-resolution grids, existing of more than 20 million cells. Consequently, computing the turbocharger compressor by using a transient, compressible CFD simulation is computationally very demanding. By applying Lighthill’s analogy, it is possible to resolve turbulent structures where they are generated and compute the pressure propagation using an additional, not that demanding, propagation grid. This allows using coarser CFD grids in the inlet and outlet section. For transferring Lighthill’s source terms from the CFD to the propagation grid, advanced interpolation algorithms are used. Furthermore, this methodology allows investigating the influence of the additions connected to the compressor, by interpolating Lighthill’s source terms onto different propagation grids. Also, since the pressure propagation is computed in the frequency domain, it is possible to investigate specific frequency ranges, which gives an additional advantage regarding computation time. The simulation results are validated by measurements of a cold gas test rig.