Simplifications Applied to Simulation of Turbulence Induced by a Side View Mirror of a Full-Scale Truck Using des

Artikel i vetenskaplig tidskrift, 2018

In this paper, the turbulent flow induced by a production side-view mirror assembled on a full-scale production truck is simulated using a compressible k- SST detached eddy simulation (DES) approach - the improved delayed DES (IDDES). The truck configuration consists of a compartment and a trailer. Due to the large size and geometric complexity of the configuration, some simplifications are applied to the simulation. A purpose of this work is to investigate whether the simplifications are suitable to obtain the reasonable properties of the flow near the side-view mirror. Another objective is to study the aerodynamic performances of the mirror. The configuration is simplified regarding two treatments. The first treatment is to retain the key exterior components of the truck body while removing the small gaps and structures. Furthermore, the trailer is shaped in an apex-truncated square pyramid. This simplification is proposed based on the assumption that the downstream flow near the trailer has limited effect on the flow near the mirror. To assess the influences of the simplifications, the flow fields computed from the original and simplified configurations are compared. The regions on the window that are subjected to significant hydrodynamic impingement are identified. The mirror and A-pillar introduce the impingement. The frequency spectra of the surface pressure fluctuations on the window are studied. The frequencies of the peaks in the spectra are the same as the characteristic frequencies of the free shear layers that develop from the mirror side-edges near the window. The simplifications are found as feasible treatments to reproduce the flow characteristics of the original geometry.