Finding Computationally Inexpensive Methods to Model the Flow Past Heavy Vehicles and the Design of Active Flow Control Systems for Drag Reduction

摘要

This paper explores the use of computational tools to analyze the aerodynamic effects that Coanda jets have on the drag, stability and maneuverability of heavy vehicles. To facilitate the analysis and understanding of the underlying causes of viscous pressure drag, this paper focuses on the study of the Ground Transportation System (GTS) model. This study is divided into two stages. The first stage uses two-dimensional geometries to explore the effects that different numerical schemes and Reynolds-Averaged-Navier-Stokes (RANS) turbulence models have on the boundary layer, flow separation, and vortex shedding. The geometries used for this study are a circular cylinder at Re = 100,000 and a square cylinder at Re = 22,000. This approach was devised to determine the effectiveness of various combinations of numerical schemes and turbulence models for the simulation of highly separated flows while minimizing the computational resources required. The second stage uses the information available from the two-dimensional bluff body results (first stage) to aid in the selection of the best suited tools to model the aerodynamic characteristics of the GTS model. This section focuses on the use of the best suited combination of numerical scheme and turbulence models to simulate the effect that the use of Coanda jets have on the aerodynamic profile of the GTS model. Finally, simulations of the GTS model equipped with Coanda jets in the trailing end were used to optimize the jet momentum coefficient for drag reduction.