Slipstream Data Analysis, Results and Discussion

Abstract

In this section the analysis and results from the freight slipstream experiments will be discussed. Throughout the analysis model scale results are presented in terms of a series of container loading configurations defined as consists 1–5, in Fig. 2.8, measured at a series of probe positions defined in Table 2.1. Results will be presented in terms of the equivalent full scale distances in various flow regions at train side and above train roof (Sects. 4.2 and 4.3). Firstly a comparison of flow development for different loading efficiencies is undertaken. By expanding this comparison and focusing on key flow regions (Sect. 4.5), conducting a series of analyses including displacement thickness, turbulence intensity and autocorrelation calculations, a thorough view of slipstream development for a Class 66 hauled container freight train and the influencing factors on slipstream development is possible. Section 4.6 discusses the influence of train speed on slipstream development at model scale. Finally comparisons are made between full and model scale data with conclusions drawn on the suitability of using model scale experiments to understand freight slipstream development (Sect. 4.7).