Ground Vehicle Aerodynamics using LS-DYNA

The use of software for the simulation of airflow around ground vehicles plays an important role in the design of a vehicle. Traditionally companies within the automotive industry sector have a Computational Fluid Dynamics department dedicated to the analysis of drag and lift with the objective of improving fuel efficiency, safety, passenger comfort, cooling systems and heat exchangers and minimizing noise. In recent years the increased pressure from government regulators for dramatic improvements in fuel efficiency has pushed the automotive industry to start innovating in lighter materials and hybrid or full electric cars. This has created new challenges in the way that traditional companies operate since the mechanical response of new materials or batteries may be greatly influenced by the fluid temperature and fluid pressure loads which in turns may affect the fluid behaviour. forcing companies to overlap efforts between a structural and fluid department. The current paper will show how the use of LSDYNA may help in reducing the burden of moving results from a CFD / thermal solver to a structural solver, preventing the degradation of the results from mapping variables and the increased cost of licences for more than one solver, simplifying a queueing system since potentially a single run could provide all the results at once and improving the accuracy since the full nonlinear model is being solved. This in turn reduces the communication time between structural and fluid departments where the interaction is sometimes informal and based on “favors” more than following project guidelines. The paper will provide an overview of the tools that LSDYNA has for CFD analysis and it will show some application examples.