Article
Engineering, Aerospace
Zhitao Zhang, Changchuan Xie, Kunhui Huang, Chao Yang
Summary: This paper quantitatively analyzes the influence of slipstream on the aerodynamic performance of a contrarotating propeller/wing system. The results show that slipstream has a significant impact on the thrust coefficient, power coefficient, and propulsion efficiency of the system. Additionally, the study finds that at small axial spacing, the thrust coefficient of the front propeller is significantly smaller than that of the rear propeller, and increasing rotational speed leads to an increase in lift coefficient and drag coefficient of the wing.
Article
Engineering, Ocean
Andrea Franceschi, Benedetto Piaggio, Diego Villa, Michele Viviani
Summary: This study investigates the main interaction effect of hull and propeller on the rudder inflow in a conventional manoeuvring simulator using a simple but robust approach. The modular/MMG based method describes the hull, rudders, and propellers with separate mathematical models to account for interaction phenomena. Numerical models developed in OpenFOAM for propeller-rudder interaction and two different approaches for hull-rudder interaction show improved accuracy compared to a calibrated semi-empirical model.
APPLIED OCEAN RESEARCH
(2022)
Article
Thermodynamics
Yang Zheng, Cheng Xu, Zheng Xinghua, Chen Haisheng
Summary: The paper presents a set of new equations SCF-RANS equations to describe turbulent flow and heat transfer of supercritical fluid, taking into account the fluctuation of thermal physical properties. Various model methods for the new correlation term have been discussed for closing the equations, providing reference information for these new correlations. The SCF-RANS equations not only offer a formulation specific to supercritical fluid flow and heat transfer, but also represent the most sophisticated form of the RANS equations with consideration of all physical properties as variables.
JOURNAL OF THERMAL SCIENCE
(2021)
Article
Mechanics
Y. Marchenay, F. Chedevergne, M. Olazabal Loume
Summary: A new modeling strategy is proposed to predict the combined effects of roughness and blowing boundary conditions. Analysis of experimental data reveals deficiencies in existing roughness corrections when predicting the effect of blowing in the presence of surface roughness.
Article
Engineering, Aerospace
Yeong-Ju Go, Joon-Hwan Bae, Jaeha Ryi, Jong-Soo Choi, Chung-Ryeol Lee
Summary: The demand for new propeller designs has increased with the development of new technology. A wind tunnel is essential to experimentally evaluate the performance of a propeller. However, implementing a large wind tunnel for meter class or larger propellers is difficult. To overcome this, studies have been conducted using scaled-down models. This study proposes a method to investigate the differences in aerodynamic performance caused by the difference in propeller scale using VLM and RANS calculations.
Article
Engineering, Multidisciplinary
Saikat Mukherjee, Hector Gomez
Summary: In this paper, a numerical algorithm is proposed to solve the Navier-Stokes-Korteweg equations, which can predict cavitation inception without assumptions about mass transfer. The proposed numerical scheme uses a modified bulk free energy and a Taylor-Galerkin discretization. It is capable of simulating high-speed flows with large pressure gradients, and is demonstrated to be accurate, stable, and robust.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Engineering, Aerospace
Yuanwei Bin, George Huang, Robert Kunz, Xiang I. A. Yang
Summary: This paper introduces a constrained model recalibration method in RANS turbulence models to address the negative impact of modifications on basic calibrations. By identifying the degrees of freedom that do not affect the basic calibrations and only modifying them when necessary, models that perform well in historically challenging flow scenarios can be trained.
Article
Thermodynamics
Yuewen Jiang, Alexander Murray, Luca di Mare, Peter Ireland
Summary: This study investigated the mesh sensitivity problem of RANS simulations by comparing two different hole geometries and seven mesh sizes under different blowing ratios. The results show that mesh convergence becomes challenging for RANS modeling, especially for fan-shaped holes.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Computer Science, Interdisciplinary Applications
Eric L. Peters, Riccardo Balin, Kenneth E. Jansen, Alireza Doostan, John A. Evans
Summary: Despite their limitations, Reynolds averaged Navier-Stokes (RANS) models are still widely used in engineering practice for modeling turbulent flows. This paper introduces a data-informed approach for improving the predictive performance of Reynolds stress models by learning components of the Reynolds stress discrepancy tensor. The proposed approach automatically generates symmetric Reynolds stress models that are Galilean and frame invariant, showing effectiveness in various turbulent flow problems.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Engineering, Aerospace
Wenbo Shi, Jie Li, Shuai Zhao, Zhao Yang
Summary: This paper presents a collaborative experimental and numerical research on the influences of propeller installation on aircraft aerodynamic performance. It shows that propeller installation leads to a decline in the maximum lift-drag ratio due to aerodynamic interactions with the airframe, and proposes center shaft extension and airframe geometry modification as effective measures to mitigate this effect. Proper spacing between propeller and airframe, along with good designs of airframe geometry, can effectively improve flow characteristics and reduce drag induced by propeller installation.
INTERNATIONAL JOURNAL OF AERONAUTICAL AND SPACE SCIENCES
(2021)
Article
Green & Sustainable Science & Technology
Alibek Issakhov, Perizat Omarova
Summary: This study developed a mathematical model to investigate fluid flow and pollutant dispersion characteristics in a certain quarter of Almaty city, Kazakhstan. It was found that setting barriers along the road can reduce the concentration of harmful substances in the pedestrian zone air.
JOURNAL OF CLEANER PRODUCTION
(2021)
Article
Computer Science, Interdisciplinary Applications
Qian-Min Huang, Yu-Xin Ren, Qian Wang, Jian-Hua Pan
Summary: This paper presents high-order compact finite volume schemes based on variational reconstruction to solve the Reynolds averaged Navier-Stokes equations. Through optimizing functional parameters and introducing an exponential decay process, the challenging issues of numerical errors on large aspect ratio grids and negative turbulent viscosity associated with high-order methods have been successfully addressed.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Multidisciplinary Sciences
Jiawei Yu, Bo Zhou, Hui Liu, Xiaoshuang Han, Guobiao Hu, Teng Zhang
Summary: Marine load plays a significant role in propeller propulsion efficiency. Understanding the wake evolution mechanism under different conditions is crucial for propeller equipment design. The wake instability characteristics are studied using the large eddy simulation (LES) method, and the composition and evolution mechanism of vortices under various load conditions are analyzed. The propeller wake is numerically simulated and compared using the unsteady Reynolds-averaged Navier-Stokes (URANS) and LES methods, and a simulation-experiment comparison is conducted. The results show that the pitch and stability of helicoidal tip vortices are influenced by the loading conditions and advance coefficients.
Article
Mechanics
Ronja Hoch, Frank-Hendrik Wurm
Summary: This study utilizes a numerical approach to predict the two-phase flow of liquid and gas inside partially filled coolant tanks and validates the numerical results with experimental data. It was found that the numerical model tends to underestimate peak pressures but shows close agreement with experimental results in simulating the liquid surface.
JOURNAL OF HYDRODYNAMICS
(2021)
Article
Engineering, Aerospace
Hugues Pantel, Fabrice Falissard, Guillaume Dufour
Summary: This work presents a body force method based on CFD and BET for propeller modeling. Best practices for source term distribution and tip-loss correction are identified through analysis. The RANS/BET body force model shows good performance in thrust and wake prediction.
Article
Engineering, Electrical & Electronic
Zhenxiao Fu, Amit Kumar Shukla, Zhiqiang Mu, Kai Lu, Yemin Dong, Ziyan Luo, Xuepeng Qiu, Zhifeng Zhu, Yumeng Yang
Summary: This work thoroughly examines the effect of out-of-plane polarized spin current through macro-spin simulations. The spin polarization is found to have a significant impact on the performance of spintronic memory and oscillator devices, emphasizing the importance of deliberate control.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Materials Science, Multidisciplinary
Peng Wu, Jun Yan, Pengli Liang, Zhifeng Zhu, Tao Wu
Summary: This study investigated the longitudinal resistivity, magnetization, and ferromagnetic resonance (FMR) properties of Mn3SnC material. Abnormal thermal hysteresis loop and angular-dependent longitudinal resistivity were observed for the first time under an in-plane magnetic field. The angular-dependent resistivity measurement revealed a correlation between the transport properties of Mn3SnC and the in-plane magnetic field orientation.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2022)
Article
Physics, Fluids & Plasmas
Zhifeng Zhu, Bo Li, Qiang Gao, Jiajian Zhu, Zhongshan Li
Summary: In this study, a femtosecond laser filament was used to trigger and guide a high-voltage DC pulse discharge, achieving spatiotemporal control of the discharge plasma. By optimizing parameters, sub-nanosecond jitter of the discharge could be achieved. This technique shows great potential in gas flow field composition measurement and studying the spatiotemporal evolution of discharge plasma.
PLASMA SCIENCE & TECHNOLOGY
(2022)
Article
Cell Biology
Haixu Xu, Jie Zhao, Jinping Li, Zhifeng Zhu, Zhaohai Cui, Ran Liu, Rong Lu, Zhi Yao, Qiong Xu
Summary: This study identifies a novel mechanism in which CAF-derived chemokine CCL5 enhances the metastasis and invasion of HCC through the HIF1 alpha/ZEB1 axis. This finding may have implications for the prognosis of HCC and provides a new therapeutic target for HCC.
CELL DEATH & DISEASE
(2022)
Article
Optics
Zhifeng Zhu, Bo Li, Qiang Gao, Ercong Gao, Zhongshan Li
Summary: The proposed femtosecond laser filament-triggered discharge ignition technique can reduce the fluctuation in ignition time and position, extend the lean ignition limit, and generate a larger initial flame kernel to reduce the flame propagation time.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Optics
Zhifeng Zhu, Qiang Gao, Bo Li, Zhanyu Feng, Ercong Gao, Ming Li, Zhongshan Li
Summary: In this paper, a new method called femtosecond laser filament-triggered discharge plasma spectroscopy is proposed for one-dimensional equivalence ratio measurements. The experimental results demonstrate the capability of this method to accurately measure the equivalence ratio in combustion flow fields, with some dependence on the temperature of the methane-air mixture.
OPTICS AND LASERS IN ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Jingwei Long, Qi Hu, Zhengping Yuan, Yunsen Zhang, Yue Xin, Jie Ren, Bowen Dong, Gengfei Li, Yumeng Yang, Huihui Li, Zhifeng Zhu
Summary: The writing performance of easy-cone magnetic tunnel junction (MTJ) and perpendicularly magnetized MTJ (pMTJ) was investigated under different temperatures using the macrospin model. The easy-cone MTJ exhibited a more stable writing performance and wider operating temperature range compared to the pMTJ. Additionally, the two types of MTJs showed opposite temperature dependence in current overdrive and write error rate, indicating that the easy-cone MTJ is more suitable for high-temperature operation.
Article
Computer Science, Information Systems
Zhilong Liu, Minggang Li, Zhifeng Zhu, Linhai Xiao, Changhua Nie, Zhangchun Tang
Summary: This paper proposes a method for identifying the health states of nuclear power main circulating pump based on ensemble empirical mode decomposition (EEMD) and support vector machine optimized by optimized quantum genetic algorithm (OQGA-SVM). The vibration signal of the main circulating pump is decomposed by EEMD to analyze the vibration signal characteristics in healthy and fault states and propose target characteristic indexes. Then, an OQGA-SVM model is established and the target characteristic indexes are used as input parameters. Experimental data analysis and validation show that the EEMD-OQGA-SVM method accurately and effectively identifies the health states of the main circulating pump, with higher accuracy and efficiency than the EEMD-SVM and EEMD-QGA-SVM methods.
Article
Materials Science, Multidisciplinary
Baofang Cai, Yihan He, Yue Xin, Zhengping Yuan, Xue Zhang, Zhifeng Zhu, Gengchiau Liang
Summary: The conventional computing method based on the von Neumann architecture faces challenges of high energy consumption and limited data exchange bandwidth. Neuromorphic computing and stochastic computing have emerged as promising alternatives due to their potential for energy-efficient and high-performance computing. Among the various unconventional computing technologies, MTJs have shown remarkable efficiency and similarity to biological nervous systems, making them a suitable candidate for implementing unconventional computing architectures.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2023)
Article
Materials Science, Textiles
Xun Zhang, Zhifeng Zhu, Jack Lin
Summary: Dimethylaminoethyl (DAE) starch was prepared by the tertiary amination of acid-converted maize starch (ACS) with 2-dimethylaminoethyl chloride hydrochloride (DAEC center dot HCl), and a series of DAE derivatives with different degrees of substitution (DS) were obtained. The amination significantly improved the bonding strength to polyester fibers and prevented difficulties in quaternized starch desizing. DAE starch showed competitive desizability during oxidant-alkali desizing. Thus, introduction of DAE groups onto ACS achieved a starch-based sizing material with strong bonding and good desizability, particularly with a DS value of 0.037-0.058 for potential application in polyester warp sizing.
FIBERS AND POLYMERS
(2023)
Article
Physics, Applied
Zhengping Yuan, Jingwei Long, Zhengde Xu, Yue Xin, Lihua An, Jie Ren, Xue Zhang, Yumeng Yang, Zhifeng Zhu
Summary: The dynamics of a spin torque-driven ferrimagnetic (FiM) system is investigated, demonstrating ultrafast switching in the picosecond range. Excessive current leads to magnetic oscillation, preventing unlimited increase in switching speed. The impact of thermal fluctuations is studied, distinguishing FiM dynamics into different regions. A significant deviation between FiM and ferromagnet (FM) is observed, with FM being insensitive to thermal fluctuations while the thermal effect is pronounced in FiM.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Condensed Matter
Weiyan Zhang, Tao Yu, Zhifeng Zhu, Binghan Li
Summary: The temperature characteristics of the read current of NOR embedded flash memory with a 1.5T-per-cell structure are analyzed and verified in this study. It is found that the read current of a programmed cell can increase, decrease, or remain unchanged with temperature, depending on the reading overdrive voltage or programming strength. By precisely controlling the programming strength and setting the reference cells to match the temperature coefficient of the tail data cells, the issue of current coefficient mismatch can be solved, leading to an improved read window.
JOURNAL OF SEMICONDUCTORS
(2023)
Article
Chemistry, Multidisciplinary
Xinran Wang, Hao Wu, Ruizhi Qiu, Xinhao Huang, Junrong Zhang, Jingwei Long, Yuxuan Yao, Yaru Zhao, Zhifeng Zhu, Junyong Wang, Shuyuan Shi, Haixin Chang, Weisheng Zhao
Summary: In this study, field-free switching at room temperature of the CoFeB/MgO heterostructure with perpendicular magnetic anisotropy is realized using large-scale, chemical vapor deposition (CVD)-grown, few-layer WTe2 thin films, thanks to unconventional spin-orbit torques (SOTs) in WTe2. Micro magnetic simulations are also used to investigate magnetization dynamics in the presence of out-of-plane polarized spin. This work paves the way for constructing all-electrical, low-power spintronic devices based on two-dimensional transition metal dichalcogenides (TMDs).
CELL REPORTS PHYSICAL SCIENCE
(2023)
Article
Physics, Applied
Zhengde Xu, Jie Ren, Zhengping Yuan, Yue Xin, Xue Zhang, Shuyuan Shi, Yumeng Yang, Zhifeng Zhu
Summary: In this paper, a trilayer AFM/insulator/heavy metal structure is proposed as the AFM memory device. The field-free switching of the AFM with a perpendicular Neel vector can be achieved by using two orthogonal currents. The device enables ultrafast switching within 40 ps and has reversibility.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Xue Zhang, Baofang Cai, Jie Ren, Zhengping Yuan, Zhengde Xu, Yumeng Yang, Gengchiau Liang, Zhifeng Zhu
Summary: In this study, a two-dimensional atomistic model is developed and a torque analysis method is provided to study ferrimagnetic oscillation. By analyzing the spatial distribution of magnetization and effective fields, we demonstrate the presence and importance of spatially nonuniform oscillation phenomena. This research provides an important tool for gaining a deeper understanding of ferrimagnets and antiferromagnets.
