Future power units of cars, e.g., the electric engine or the fuel cell, generate little noise. Consequently, the noise connected to auxiliary units becomes more dominant. Thereby, especially rotating components are of great importance, e.g., the cooling fan of a battery unit or the turbocharger of fuel cells. Since performing complex measurements are expensive and require a lot of time, simulations enhance current development processes. Hence, we present two different aeroacoustic simulation approaches applied to two examples of the automotive industry.