Development of a Numerical Investigation Framework for Ground Vehicle Platooning

Abstract

This paper presents a study on the flow dynamics involving vehicle interactions. In order to do so, this study first explores aerodynamic prediction capabilities of popular turbulence models used in computational fluid dynamics simulations involving tandem objects and thus, ultimately presents a framework for CFD simulations of ground vehicle platooning using a realistic vehicle model, DrivAer. Considering the availability of experimental data, the simulation methodology is first developed using a tandem arrangement of surface-mounted cubes which requires an understanding on the role of turbulence models and the impacts of the associated turbulence model closure coefficients on the prediction veracity. It was observed that the prediction accuracy of the SST k−ω turbulence model can be significantly improved through the use of a combination of modified values for the closure coefficients. Additionally, the initial validation studies reveal the inability of the Unsteady Reynolds-Averaged Navier-Stokes (URANS) approach to resolve the far wake, and its frailty in simulating tandem body interactions. The Improved Delayed Detached Eddy Simulations (IDDES) approach can resolve the wakes with a reasonable accuracy. The validated simulation methodology is then applied to the fastback DrivAer model at different longitudinal spacing. The results show that, as the longitudinal spacing is reduced, the trailing car’s drag is increased while the leading car’s drag is decreased which supports prior explanations of vortex impingement as the reason for drag changes. Additionally, unlike the case of platooning involving Ahmed bodies, the trailing model drag does not return to an isolated state value at a two car-length separation. However, the impact of the resolution of the far wake of a detailed DrivAer model, and its implication on the CFD characterization of vehicle interaction aerodynamics need further investigations.

Improving the Energy Efficiency of Vehicles by Ensuring the Optimal Value of Excess Pressure in the Cabin Depending on the Travel Speed

“…Figure 8 shows a graph of the dependence of the maximum pressure value on the locomotive body on the speed of movement. It can be seen that the pressure increases proportionally to the square of the velocity, which is consistent with the known formulas of the resistance force [37][38][39][40][41][42]. Figure 8 shows a graph of the dependence of the maximum pressure value on the locomotive body on the speed of movement.…”

“…The values of excess internal pressure P int , which ensures the operation of the climate system under different operating modes, are studied numerically based on the Navier-Stokes equations, and are also compared with the results of an approximate applied formula. The numerical solution of the Navier-Stokes equations is widely used for analyzing vehicle aerodynamics in research [34][35][36][37]. CFD models with large-scale grids and large time steps based on Reynolds averaging Navier-Stokes (RANS) approaches are currently popular.…”

Application of the DMD Approach to High-Reynolds-Number Flow over an Idealized Ground Vehicle

“…An example is platooning, where drag reduction is desired via vehicle-to-vehicle interaction of aerodynamics where one or more trailing cars follow a lead car in close proximity. Active control systems are believed to make platooning feasible for all vehicles, as autonomous vehicles allow for closer proximity due to reduced reaction times [15][16][17]. Before a control signal can be applied to the moving vehicle, predictions of the future state of aerodynamic forces and moments are required.…”