Paper Title
Numerical Validation and Analysis of Tractor-Trailer at Varying Cross Wind Angles

Abstract
For the design and performance of vehicle, accurate calculation of drag and lift coefficient is a significant process step. Higher value of aerodynamic coefficients results in more fuel consumption. This phenomenon is predominantly significant, when the speed of vehicle is above 60 kmph. Moreover, with higher velocity, vehicle stability becomes a major issue especially due to under-steering or over-steering. Hence, quantification of the aerodynamic loads during windy conditions becomes important to evaluate the risks associated with them. It is always recommended to validate wind tunnel experiment with numerical simulation to ensure safety and performance of the vehicle. In the present study, an attempt is made to analyze the aerodynamic loads on Tractor-Trailer. This study was conducted at an average speed (54kmph) of vehicle at different wind flow angles. The flow considered here is turbulent flow. The Lift, Drag and side forces, moments for Tractor-Trailer vehicle are computed numerically using CFD analysis. The modeling of the Tractor-Trailer was performed using SolidWorks-14 modeling software and the model was then imported to Ansys (CFD-Fluent)-15 for analysis. The various test cases were simulated in Ansys-Fluent to obtain the data for further review, analysis and optimization. The trends of aerodynamic forces were plotted with respect to test condition’s, which includes wind flow angles and nature of wind flow. The results of the numerical simulations were compared and validated with experimental conclusions as available in the literature. Design modifications to the Tractor-Trailer are further undertaken in order to ascertain and capture the changes in the aerodynamic coefficients. Keywords - Aerodynamic Coefficients, CFD, Tractor-Trailer, Turbulent Flow, Wind Angles