{"title":"Flow field analysis of Vortex Ring State through descent experiments and simulations with a quadcopter","authors":"Ryuki Mori , Ayato Takii , Masashi Yamakawa , Shinichi Asao , Seiichi Takeuchi , Yusei Kobayashi , Yongmann M. Chung","doi":"10.1016/j.jocs.2025.102528","DOIUrl":null,"url":null,"abstract":"<div><div>Vortex Ring State (VRS), which can occur during descent of rotorcraft including drones, is a flow field phenomenon that causes instability and may result in a crash. In the Lecture Note, Mori (2024) focused on the rotor model of a quadcopter to analyze the flow field during VRS [1]. In this study which is an extension of that research, descent experiments using a quadcopter drone was conducted to collect flight data on the descent speed and attitude angle at which VRS can occur. As a result, large roll angle change was observed at descent speeds close to hovering induced velocity. Next, descent simulation using the same quadcopter model as in the descent experiment was conducted using the velocity data obtained in the real experiments to verify the flow field in the VRS. The numerical fluid dynamics simulations were performed by combining Moving Computational Domain (MCD) method and sliding mesh method, and by considering the coupling between the fluid and the rigid body. As a result, vortex ring was observed around the rotors when the descent velocity was close to the hovering induced velocity. From the Q criterion isosurface, it is considered that the flow including the disturbance generated by the rotors is stagnant around the rotors, which leads to the instability of the quadcopter. Furthermore, the lift value fluctuation rate of more than 15 % indicates that VRS was likely to have occurred at descent speeds close to the hovering induced speed.</div></div>","PeriodicalId":48907,"journal":{"name":"Journal of Computational Science","volume":"85 ","pages":"Article 102528"},"PeriodicalIF":3.1000,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Computational Science","FirstCategoryId":"94","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1877750325000055","RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS","Score":null,"Total":0}
引用次数: 0
Abstract
Vortex Ring State (VRS), which can occur during descent of rotorcraft including drones, is a flow field phenomenon that causes instability and may result in a crash. In the Lecture Note, Mori (2024) focused on the rotor model of a quadcopter to analyze the flow field during VRS [1]. In this study which is an extension of that research, descent experiments using a quadcopter drone was conducted to collect flight data on the descent speed and attitude angle at which VRS can occur. As a result, large roll angle change was observed at descent speeds close to hovering induced velocity. Next, descent simulation using the same quadcopter model as in the descent experiment was conducted using the velocity data obtained in the real experiments to verify the flow field in the VRS. The numerical fluid dynamics simulations were performed by combining Moving Computational Domain (MCD) method and sliding mesh method, and by considering the coupling between the fluid and the rigid body. As a result, vortex ring was observed around the rotors when the descent velocity was close to the hovering induced velocity. From the Q criterion isosurface, it is considered that the flow including the disturbance generated by the rotors is stagnant around the rotors, which leads to the instability of the quadcopter. Furthermore, the lift value fluctuation rate of more than 15 % indicates that VRS was likely to have occurred at descent speeds close to the hovering induced speed.
期刊介绍:
Computational Science is a rapidly growing multi- and interdisciplinary field that uses advanced computing and data analysis to understand and solve complex problems. It has reached a level of predictive capability that now firmly complements the traditional pillars of experimentation and theory.
The recent advances in experimental techniques such as detectors, on-line sensor networks and high-resolution imaging techniques, have opened up new windows into physical and biological processes at many levels of detail. The resulting data explosion allows for detailed data driven modeling and simulation.
This new discipline in science combines computational thinking, modern computational methods, devices and collateral technologies to address problems far beyond the scope of traditional numerical methods.
Computational science typically unifies three distinct elements:
• Modeling, Algorithms and Simulations (e.g. numerical and non-numerical, discrete and continuous);
• Software developed to solve science (e.g., biological, physical, and social), engineering, medicine, and humanities problems;
• Computer and information science that develops and optimizes the advanced system hardware, software, networking, and data management components (e.g. problem solving environments).