Mehmet Karahan^*

CMC-Computers, Materials & Continua, Vol.82, No.1, pp. 777-798, 2025, DOI:10.32604/cmc.2024.059123 - 03 January 2025

Abstract Advances in software and hardware technologies have facilitated the production of quadrotor unmanned aerial vehicles (UAVs). Nowadays, people actively use quadrotor UAVs in essential missions such as search and rescue, counter-terrorism, firefighting, surveillance, and cargo transportation. While performing these tasks, quadrotors must operate in noisy environments. Therefore, a robust controller design that can control the altitude and attitude of the quadrotor in noisy environments is of great importance. Many researchers have focused only on white Gaussian noise in their studies, whereas researchers need to consider the effects of all colored noises during the operation of… More >

Haoyu Cui¹, Congxin Yang^1,2,*, Yanlei Guo¹, Tianzhi Lv¹, Sen Zhao¹

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.12, pp. 2907-2926, 2024, DOI:10.32604/fdmp.2024.055301 - 23 December 2024

Abstract Most of existing methods for the safety assessment of the primary cooling loop of nuclear reactors in conditions of reactor coolant pump (RCP) failure (rotor seizure accident) essentially rely on the combination of one-dimensional theory and experience. This study introduces a novel three-dimensional model of the ‘Hualong-1’ (HPR1000) primary loop and uses the method of matching the resistance characteristics of the tube to ensure that the main pump operates at the rated operating condition. In particular, the three-dimensional unsteady numerical calculation of the RCP behavior in the rotor-seizure accident condition is carried out in the More >

Taha Yacine Trad^1,*, Kheireddine Choutri¹, Mohand Lagha¹, Souham Meshoul², Fouad Khenfri³, Raouf Fareh⁴, Hadil Shaiba⁵

CMC-Computers, Materials & Continua, Vol.81, No.3, pp. 4757-4786, 2024, DOI:10.32604/cmc.2024.055634 - 19 December 2024

Abstract The popularity of quadrotor Unmanned Aerial Vehicles (UAVs) stems from their simple propulsion systems and structural design. However, their complex and nonlinear dynamic behavior presents a significant challenge for control, necessitating sophisticated algorithms to ensure stability and accuracy in flight. Various strategies have been explored by researchers and control engineers, with learning-based methods like reinforcement learning, deep learning, and neural networks showing promise in enhancing the robustness and adaptability of quadrotor control systems. This paper investigates a Reinforcement Learning (RL) approach for both high and low-level quadrotor control systems, focusing on attitude stabilization and position… More >

Linlin Zhang, Lvzhao Bai, Jianshu Liang, Zhiying Qin^*, Yuejing Zhao

Computer Systems Science and Engineering, Vol.48, No.6, pp. 1557-1579, 2024, DOI:10.32604/csse.2024.054237 - 22 November 2024

Abstract Quadrotor unmanned aerial vehicles (UAVs) are widely used in inspection, agriculture, express delivery, and other fields owing to their low cost and high flexibility. However, the current UAV control system has shortcomings such as poor control accuracy and weak anti-interference ability to a certain extent. To address the control problem of a four-rotor UAV, we propose a method to enhance the controller’s accuracy by considering underactuated dynamics, nonlinearities, and external disturbances. A mathematical model is constructed based on the flight principles of the quadrotor UAV. We develop a control algorithm that combines humanoid intelligence with… More >

Chunxiu Ji¹, Dan Xie^1,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.30, No.2, pp. 1-1, 2024, DOI:10.32604/icces.2024.012592

Abstract The persistence of accidents attributed to structural damage in traditional rotor blades remains a pressing concern for aeronautical experts. Given the infrequency of flutter in undamaged blades, this study directs its attention to a rotor blade afflicted with structural damage, with a primary objective of discerning flutter occurrences, elucidating underlying mechanisms, and scrutinizing resultant aeroelastic responses. This paper presents an investigation into the flutter mechanism observed in transonic rotor blades subjected to structural damage, employing the Spectral Proper Orthogonal Decomposition(SPOD) method. The study aims to understand the dynamics of flutter under the influence of structural More >

Zhuo Liu, Yecui Yan^*

Frontiers in Heat and Mass Transfer, Vol.22, No.5, pp. 1443-1460, 2024, DOI:10.32604/fhmt.2024.056091 - 30 October 2024

Abstract The external rotor hub motor adopts direct drive mode, no deceleration drive device, and has a compact structure. Its axial size is smaller than that of a deceleration-driven hub motor, which greatly reduces the weight of the vehicle and increases the cruising range of the vehicle. Because of the limited special working environment and performance requirements, the hub motor has a small internal space and a large heat generation, so it puts forward higher requirements for heat dissipation capacity. For the external rotor hub motor, a new type of in-tank water-cooled structure of hub motor… More >

Abdellatif El Hannaoui^1,*, Rachid Boutarfa¹, Chadia Haidar²

Frontiers in Heat and Mass Transfer, Vol.22, No.3, pp. 733-746, 2024, DOI:10.32604/fhmt.2024.050520 - 11 July 2024

Abstract The proposed work focuses on the in-depth study of convective heat transfer in the unconfined air gap of a discoidal rotor-stator system. The rotary cooling mechanism is achieved by the injection of two air jets, while the cavity geometry is characterized by a dimensionless parameter G. The numerical analysis primarily concentrated on the effect of flow velocity and rotation on the heat exchange process. More precisely, the range of analysis extends from the rotational Reynolds number to , while varying the Reynolds value of the jet in a range from to . To carry out More >

Mengdong An¹, Weiyuan Zhong¹, Wei Xu², Xiuli Wang^1,*

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.6, pp. 1331-1349, 2024, DOI:10.32604/fdmp.2023.046604 - 27 June 2024

Abstract The reactor coolant pump (RCP) rotor seizure accident is defined as a short-time seizure of the RCP rotor. This event typically leads to an abrupt flow decrease in the corresponding loop and an ensuing reactor and turbine trip. The significant reduction of core coolant flow while the reactor is being operated at full load can have very negative consequences. This potentially dangerous event is typically characterized by a complex transient behavior in terms of flow conditions and energy transformation, which need to be analyzed and understood. This study constructed transient flow and rotational speed mathematical More > Graphic Abstract

Cheng-Yeh Li, Jui-Hsiang Kao^*

CMES-Computer Modeling in Engineering & Sciences, Vol.138, No.3, pp. 2277-2304, 2024, DOI:10.32604/cmes.2023.030215 - 15 December 2023

Abstract The performance of a water jet propulsion system is related to the inlet duct, rotor, stator, and nozzle. Generally, the flow inlet design must fit the bottom line of the hull, and the design of the inlet duct is often limited by stern space. The entire section, from the rotor to the nozzle through the stator, must be designed based on system integration in that the individual performance of these three components will influence each other. Particularly, the section from the rotor to the nozzle significantly impacts the performance of a water jet propulsion system.… More >

Chunxiu Ji¹, Dan Xie^1,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.25, No.3, pp. 1-1, 2023, DOI:10.32604/icces.2023.010329

Abstract Blade flutter is a complex phenomenon that can lead to serious damage or failure of turbomachinery systems. Predicting and mitigating blade flutter is therefore an important aspect of the design and analysis of these systems[1]. In this paper, we present a comparative study of two representative methods for blade flutter predictions: the energy method and the computational fluid dynamics/computational structural dynamics (CFD/CSD) coupled time-domain method. The energy method is a decoupled approach that uses a simplified model of the blade and fluid-structure interaction to calculate the stability boundaries of the system[2]. The time-domain method, on… More >