Base wake dynamics and its influence on driving stability of passenger vehicles in crosswind
Artikel i vetenskaplig tidskrift, 2022

The unsteady flow around a travelling vehicle induces fluctuating aerodynamic loads. Automotive manufacturers usually set targets on the time-averaged lift forces to ensure good straight-line stability performance at high speeds. These targets are generally sufficient in preventing unstable vehicle designs. Yet, small changes in averaged values occasionally yield unexpectedly large differences in the stability performance, indicating that the changes in averaged normal loads cannot solely explain these differences. The unsteady aerodynamic effects on driving stability are, therefore, an interesting topic to study. The objective of the present work is to investigate the differences in wake dynamics and fluctuating aerodynamic loads for two variants of a roof spoiler on a sports utility vehicle: a baseline that was known to cause stability issues and an improved design which resolved them. The vehicle designs were investigated using accurate time-resolved CFD simulations for a set of crosswind conditions. The unsteady aerodynamic response was coupled to a vehicle dynamics model to analyse the resulting impact on driving stability. It was shown that in crosswinds the baseline spoiler, contrary to the improved spoiler, has bi-stable wake dynamics that induce lift force fluctuations at frequencies close to the 1st natural frequency of the rear suspension.

Wake dynamics

Crosswind

CFD

Lift

Driving stability

Roof spoiler

Vehicle dynamics

Aerodynamics

Författare

Adam Brandt

Chalmers, Mekanik och maritima vetenskaper, Fordonsteknik och autonoma system

China-Euro Vehicle Technology (CEVT) AB

Simone Sebben

Chalmers, Mekanik och maritima vetenskaper, Fordonsteknik och autonoma system

Bengt J H Jacobson

Chalmers, Mekanik och maritima vetenskaper, Fordonsteknik och autonoma system

Journal of Wind Engineering and Industrial Aerodynamics

0167-6105 (ISSN)

Vol. 230 105164

Styrkeområden

Transport

Ämneskategorier

Rymd- och flygteknik

Infrastrukturteknik

Farkostteknik

DOI

10.1016/j.jweia.2022.105164

Mer information

Senast uppdaterat

2022-10-21