Article
Engineering, Marine
Chang-Lin Meng, Zhi-Jun Shuai, Tao Yu, Ke-Xin Ren, Jie Jian, Xi Wang, Dong-Hua Wang, Wan-You Li, Chen -Xing Jiang
Summary: In this paper, the unsteady exciting characteristics of a marine propeller influenced by the shafting whirling vibration effect are numerically studied by employing the dynamic sliding multi-region method and a Reynolds-averaged Navier-Stokes equation model. The propeller and shafting system inevitably vibrates during operation, where the multiple exciting forces can cause the shafting to rotate and whirl around different center lines at the same time. The influence mechanism of different whirling motions on the propeller exciting characteristics and propeller velocity field fluctuation are studied.
Article
Engineering, Ocean
Jiasheng Li, Yegao Qu, Yong Chen, Hongxing Hua
Summary: The paper presents a numerical method for analyzing the hydroelastic behaviors of fully coupled marine propeller and shafting system immersed in water, using a panel method and a finite element method. A modal reduction technique is utilized to overcome the low numerical efficiency caused by the propeller's asymmetric added matrices. The validity of the method is confirmed by comparing the results with finite element analysis solutions, showing the importance of considering the coupling of fluid, propeller, and shaft for predicting dynamic system responses.
APPLIED OCEAN RESEARCH
(2021)
Article
Mechanics
Lianzhou Wang, Tiecheng Wu, Jie Gong, Yiren Yang
Summary: The study investigates propeller wake instability mechanisms using simulation methods, analyzing the flow physics that drive the tip vortex instability process. The research extends understanding of propeller wake instability inception mechanisms under heavy loading conditions.
Article
Engineering, Multidisciplinary
Jabbar Firouzi, Hassan Ghassemi, Mohammad Shadmani
Summary: This paper investigates the torsional-longitudinal vibrations of marine propeller shafting systems by developing an integrated mathematical formulation, considering lumped effects on the main shaft and blade deformations. The non-FEM distributed-parameter modeling and Galerkin method are employed to analyze the problem, showing that taking blade deformations into account is advantageous for vibration analysis.
APPLIED MATHEMATICAL MODELLING
(2021)
Article
Mechanics
Antonio Posa
Summary: Large-eddy simulation with a grid of 5 billion points was used to analyze the turbulence properties of tip and hub vortices produced by a marine propeller. The turbulence at the core of the tip vortices starts as isotropic and evolves towards an axisymmetric state as instability grows. The break-up of the tip vortices leads to a return to isotropy. In contrast, the turbulence at the core of the hub vortex develops into an axisymmetric state dominated by radial and azimuthal velocity fluctuations.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Thermodynamics
Jiaqi Luo, Qiang Zhou, Tao Jin
Summary: A computational fluid dynamics (CFD) model is developed to simulate the nonlinear phenomena in a gas-liquid standing-wave thermoacoustic engine. The model accurately predicts the onset and steady-state performances of the experimental system. The nonlinear dynamic and acoustic phenomena of the engine are analyzed, as well as the multi-dimensional flow effect and mass streaming.
APPLIED THERMAL ENGINEERING
(2022)
Article
Engineering, Marine
Chang-Lin Meng, Lie-Yi Dong, Dong-Hua Wang, Jia-Xuan He, Zhi-Jun Shuai, Wan-You Li, Shi-Wei Ni, Chen-Xing Jiang
Summary: This study investigates the unsteady propeller hydrodynamic excitation influenced by shafting whirling vibration under different nonuniform inflow conditions. The results show that the two-way coupling affects the amplitude and phase of the excitation, while the frequency remains unchanged. The radial excitation amplitude increases by 31.65% after considering the two-way coupling.
Article
Engineering, Aerospace
Tao Zhang, George N. Barakos
Summary: This paper presents high-fidelity numerical investigations of rotor/propeller aerodynamic interactions related to thrust-augmented compound rotorcraft. The study uses high-fidelity CFD simulations and compares the results with experimental data from ONERA. The simulations show that actuator disk modeling is an effective method for simulating the main rotor, and ducting the propeller provides significant alleviation of aerodynamic interference.
AEROSPACE SCIENCE AND TECHNOLOGY
(2022)
Article
Engineering, Marine
Shine Win Naung, Mahdi Erfanian Nakhchi, Mohammad Rahmati
Summary: High-fidelity Large Eddy Simulations were used to study the effects of blade oscillation on the unsteady flow behavior and performance of composite marine propeller blades. The results showed that blade oscillation has a significant impact on vortex generation, which could affect the performance and structural integrity of the composite blades.
Article
Mechanics
A. Posa
Summary: Large-eddy simulations are used to study the tip vortices shed by a hydrofoil in a system with a propeller. The results show that the tip vortices have a significant impact on the performance, turbulence levels, and pressure fluctuations of the system.
Article
Mechanics
Xiang Fan, Jin-jing Tang, Yu-xin Zhang, Hai-su Sun, Yi-qing Gu, Jing-xin Zhang
Summary: This study uses a numerical tank to simulate ship stopping maneuver, validated the numerical model and investigated the effects of ship speed and propeller speed on propeller loads, showing dimensionless relations through J-K-T and J-K-Q curves, and examining flow structures and propeller pressure under different J values.
JOURNAL OF HYDRODYNAMICS
(2021)
Article
Engineering, Marine
Zhenguo Zhang, Xinxing Ma, Haiting Yu, Hongxing Hua
Summary: The paper focuses on the fast uncertainty quantification and sensitivity analysis of marine shafting systems, developing a statistical surrogate model and conducting a variance-based global sensitivity analysis. It investigates the effects of uncertainties on the stochastic dynamic properties of the shafting system through uncertainty envelopes and probability density functions, comparing numerical results with traditional Monte Carlo simulations.
Article
Engineering, Marine
Lie Chen, Shun Wang, Jiangming Ding, Yutao Wang, Peter Bennett, Jian Cheng, Qibiao Yang, Dun Liu
Summary: In this study, two superhydrophobic blade surfaces were prepared using nanosecond laser processing and superhydrophobic coating. Numerical calculations showed that these superhydrophobic propellers had higher efficiency throughout their operating conditions. Towing tank tests demonstrated that the superhydrophobic propellers generated greater thrust but required more torque, and the changes in thrust and torque were attributed to the pressure differential and the gradual loss of the air layer and increased shape resistance. The research highlighted the significant impact of superhydrophobic surfaces on propeller efficiency and extended the engineering applications in vessel propulsion.
Article
Engineering, Aerospace
Keisuke Otsuka, Alfonso del Carre, Rafael Palacios
Summary: This study presents a nonlinear aeroelastic analysis framework for high-aspect-ratio wings, which includes the aerodynamic effects of propellers. By utilizing a novel averaged vortex cylinder method, the induced velocities of the propeller vortex cylinder can be efficiently calculated without sacrificing accuracy, and then used in the wing aerodynamic force calculation. The framework is validated through comparison with other formulations, showing that the propeller-induced axial velocity can cause deflection changes and decrease vibration amplitudes.
JOURNAL OF AIRCRAFT
(2022)
Article
Mechanics
Antonio Posa, Riccardo Broglia, Mario Felli, Marta Cianferra, Vincenzo Armenio
Summary: The acoustic signature of a seven-bladed submarine propeller is characterized using the acoustic analogy method. Results show that the nonlinear terms of the governing equation dominate away from the propeller, while the linear terms decay downstream. The propeller's acoustic signature is mainly tonal in the near field, due to the thickness and loading components of noise from the surface of the propeller and the periodic perturbation caused by its tip vortices. The faster development of instability in the tip vortices compared to the hub vortex leads to an energy cascade towards higher frequencies, contributing to broadband noise.
JOURNAL OF FLUID MECHANICS
(2022)