Breaking records using digital aero development

The Mercedes-Benz Concept IAA

When the Mercedes-Benz management decided in late summer 2014 to build the Concept IAA (Intelligent Aerodynamic Automobile) show car for the 2015 Frankfurt Automobile Show, it was clear that this would be a very challenging year for all involved groups like stylists, CAD-designers, manufacturers and aerodynamic engineers.

Adjoint based optimization connected with the CAD

Application of adjoint method in computational fluid dynamics makes the calculation of gradients of objective functions with respect to design parameters computationally affordable. By applying traditional methods, e.g methods based on finite differences, the number of simulations required for the gradient calculations increases drastically with an increasing number of design parameters. Through the use of adjoint method is it possible to calculate all gradients in “one shot”.

Direct noise simulation of flow induced whistle

In this study the attention was focused on a secondary noise source of the vehicle such as the refrigerant system. The problem was initially described as an annoying whistle noise, which was clearly audible inside a vehicle cabin. The issue frequency identification through time-frequency plots showed a typical acoustic resonance occurring along the refrigerant gas duct, at a specific flow speed. This phenomenon was worsening significantly the sound quality of the vehicle interior noise.