Hydrodynamic force calculation on smooth and grooved tires using CFD.

摘要

Hydroplaning in tires driving over a standing layer of water on a road is investigated. The Hydroplaning effects of a smooth and grooved tire are computed. A numerical procedure to determine the lift and drag forces acting on a tire at certain velocity is developed and the tendency of tire to hydroplane is predicted.; A computational fluid dynamics (CFD) program is utilized for analyzing this complex two-phase flow field. An efficient free surface model called, Volume of Fluid (VOF) defines the three-dimensional flow surrounding the tire. The program uses hybrid grid in a finite volume formulation to solve the Navier-Stokes equation. These fluid mechanics equations results in the pressure distribution and the velocity vectors. The integration of pressure distribution acting on the tire surface yields the lift and drag forces as well as the lift and drag coefficients. The hydroplaning simulation predicts different parameters such as velocity variation, water flow and the effect of tread pattern on hydroplaning. The calculation is performed at three different velocities, 30, 60 and 90 km/h and two different water heights 8 and 12 mm. It is shown that tire tread patterns can substantially alleviate hydroplaning effects on a tire over vehicle driving speed ranges. The results obtained after studying the flow for a number of different cases and input parameters qualitatively support the earlier work carried out by other investigators.; Appendices to the thesis give a overview of the computation and setting up CFD package, FLUENT.