1995-02-01

Practical Aerodynamic Simulations (CD, CL, CYM) Using a Turbulence Model and 3rd-Order Upwind Scheme 950629

Conventional aerodynamic simulations have been carried out by using Supercomputer and over a hundred thousand grid points. It takes a long CPU time to get a result. So this method has been mainly used as a research and demonstration tool.In this paper a practical aerodynamic simulation for early phases of the automobile design is presented. This new method basically uses the conventional (wall function used) k-ε turbulent model which is regarded as the most promising in engineering and industrial fields.Firstly, the third-order upwind scheme is introduced to the convective term to improve flow field and pressure distribution. Secondly, the modified turbulent energy production method (M.P.Method) which was proposed by B.E. Launder[3] in 1993, is introduced to the k-ε turbulent model to reduce the excessive generation of turbulent kinetic energy.It takes 20 hours to generate a computational mesh from design CAD data by a new semi-automatic mesh generator and 10 hours to get the steady flow result by using EWS (IRIS Indigo2 R4400, 1CPU).It takes only 4 days to get an aerodynamic solution within an error of 5% for CD (Drag Coefficient) and CL (Lift Coefficient). This new method has been applied to the aerodynamic simulation system, a designer has been able to carry out the practical simulation on early designing phase of an automobile.We also present a CYM (Yawing Moment Coefficient) simulation between 0 and 45 degree and the influence of a outside rear view door mirror on Two-Box automobile.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Members save up to 43% off list price.
Login to see discount.
Special Offer: With TechSelect, you decide what SAE Technical Papers you need, when you need them, and how much you want to pay.
X