## 6 Conclusions and Discussions  
This study utilizes wind tunnel experiments and CFD numerical simulations to investigate the drag reduction impact of different drafting formations. The main conclusions can be drawn as follows:  
Firstly, this paper introduces a method to evaluate drag reduction consistency in drafting formations with different numbers of race walkers by comparing wind tunnel experiments and CFD simulations using the drag reduction rate \(\theta\). The results show that both methods have drag reduction rate errors below 10%, which is better than the comparison of single-person drag calculations. This underscores that in drafting formations, athlete positioning is the key factor influencing drag reduction, with model posture differences having a minimal impact. This article supports this assertion by comparing the drag reduction rates before and after mirroring the postures of the front race walker in the optimal double formation, resulting in rates of 65% and 62%, respectively, with an error of 4.8%. Furthermore, the drag reduction rate discrepancies between this article and [PERSON]'s optimal double and triple formations are both below 6%, further validating this point. These research findings not only emphasize the importance of athletes' relative positions in formation walking for drag reduction effects but also provide a reliable basis for using static models to study drag reduction effects in drafting formations. Secondly, the drag reduction in 15 different drafting formations was evaluated using both CFD simulations and wind tunnel experiments. Our findings indicate that the optimal drafting formations are consistent with different numbers of race walkers in both CFD simulations and wind tunnel experiments. The core race walker experiences drag reductions of 67%, 66%, and 81% in double, triple, and quadruple formations in the wind tunnel experiment, and 65%, 72%, and 85% in the CFD simulations. The utilization of CFD analysis to investigate drafting formations in race walking revealed that drag reduction is achieved through the shielding effect of the race walkers on the oncoming flow. This effect minimizes the impact of fluid on the core race walker, resulting in a reduced pressure difference between the front and rear. Finally, the effect of drag reduction on performance is analyzed by an empirical model for mechanical power output. Using a 20 km race walk as a case study, the benefits of different drafting formations with race walkers are evaluated in terms of sports economy, speed, and performance. The results indicate that, compared to race walking alone, the core race walker in the optimal double, triple, and quadruple drafting formations experienced improved sports economy of 4.4%, 4.9%, and 5.7%, increased speed by 3.61%, 4.03%, and 4.67%, and enhanced performances by 173.8 s (3.48%), 193.5 s (3.87%), and 223.3 s (4.47%). It is worth mentioning that in the CFD simulation, the race walkers' model remains static, and only one model is used in the formation with a fixed posture, which may differ from the situation in actual race walking. However, the main research purpose of this paper was to focus on the interaction between air and race walkers in the drafting formation and the drag reduction effect. The study found that the drag reduction rates of different race walkers in the formation, both in the wind tunnel experiment and the CFD simulation with a single model, are essentially the same. This result also confirms that the spacing between race walkers, rather than the differences in body posture, is the most critical factor affecting the drag reduction effect and the drag reduction mechanism of the drafting formation. Therefore, this study suggests that CFD simulations using specific postures can provide a foundation for understanding drag reduction effects and mechanisms in race walkers within various formations.