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Aerodynamic characteristics and trajectory analysis of badminton shuttlecocks

Zhou Lin

Acta of Bioengineering and Biomechanics

2024

Vol. 26, no. 4

29--37

This study aimed to investigate the aerodynamic characteristics and trajectory behavior of badminton shuttlecocks, focusing on the effects of design factors such as porosity, flexibility, and feather geometry on flight performance. The main research question was how shuttlecock design influences aerodynamic forces and resulting trajectories. Methods: Wind tunnel tests were conducted on two feather and two synthetic shuttlecocks to measure drag, lift, and pitching forces across speeds of 10–50 m/s and angles of 0–20°. Empirical correlations for drag and lift coefficients were derived via regression analysis. The effects of gaps and rotation were evaluated by modifying shuttlecocks. Trajectories were simulated by numerically integrating the equations of motion using the empirical force correlations and validated against high-speed video of players hitting shuttlecocks. Results: Premium shuttlecocks displayed lower drag and higher lift than budget models. Feather shuttlecocks maintained higher rotation rates at high speeds compared to synthetic ones. Sealing gaps reduced drag by up to 10% for 75% sealed gaps. Stiffening synthetic skirts improved performance closer to feather shuttlecocks. Simulations matched experimental trajectories within 5% deviation for key metrics across different shots and shuttlecock types. Conclusions: Shuttlecock design significantly impacts aerodynamic forces and flight trajectories. Factors such as porosity, skirt flexibility and feather shape play crucial roles in performance. The developed simulation methodology can aid players in optimizing shots and manufacturers in designing better shuttlecocks. This research enhances understanding of shuttlecock aerodynamics and provides a foundation for future equipment innovations in badminton.

Review of the Essential Characteristics of 2,4-Dinitroanisole

Meng Jun-jiong, Zhou Lin, Miao Fei-chao

Central European Journal of Energetic Materials

2023

Vol. 20, no. 1

50--74

With the development of weapons and ammunition to achieve more powerful and safer functional systems, 2,4-dinitroanisole (DNAN), used as an insensitive melt-cast matrix explosive, has received widespread attention. Various countries have conducted significant research and developed a series of DNAN-based explosive formulations in recent years. However, some inherent limitations of DNAN have enormously restricted its comprehensive application in weapons. In this paper, the progress of DNAN research in recent years is systematically reviewed from the aspects of its essential characteristics, such as physical properties (melting point, shrinkage, irreversible expansion, solubility, and mechanical properties), sensitivity and safety, stability, compatibility, and oxygen balance and energy. The advantages and disadvantages of DNAN are analyzed, and methods to solve these limitations are described. Furthermore, several important directions to be studied in future research are highlighted, including the study of DNAN binary eutectic mixtures mechanisms, control of crystal transformation, and improvements in mechanical properties.