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Parallelization strategies for resolved simulations of fluid-structure-particle interactions

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Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 857-872页

作者： Jianhua QIN fei liao Guodan DONG Xiaolei YANG The State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China Interdisciplinary Center for Fundamental and Frontier Sciences Nanjing University of Science and TechnologyJiangyin 214443Jiangsu ProvinceChina School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China School of Engineering Sciences University of Chinese Academy of SciencesBeijing 100049China

Fluid-structure-particle interactions in three spatial dimensions happen in many environmental and engineering *** paper presents the parallel algorithms for the hybrid diffuse and sharp interface immersed boundary(IB)method developed in our previous *** the moving structure modeled using the sharp interface IB method,a recursive box method is developed for efficiently classifying the background grid *** the particles modeled using the diffuse interface IB method,a‘master-slave’approach is *** the particle-particle interaction(PPI)and particle-structure interaction(PSI),a fast algorithm for classifying the active and inactive Lagrangian points,which discretize the particle surface,is developed for the‘dry’contact *** results show that the proposed recursive box method can reduce the classifying time from 52seconds to 0.3 *** parallel efficiency is obtained for cases with different particle ***,the lubrication model is utilized when a particle approaches a wall,enabling an accurate simulation of the rebounding phenomena in the benchmark particle-wall collision *** last,the capability of the proposed computational framework is demonstrated by simulating particle-laden turbulent channel flows with rough walls.

关键词： particle-resolved direct numerical simulation particle-laden flow complex geometry resolved fluid-structure-particle interaction(RFSPI) immersed boundary(IB)method

On the capability of the curvilinear immersed boundary method in predicting near-wall turbulence of turbulent channel flows

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Theoretical & Applied Mechanics Letters 2021年第4期11卷 213-218页

作者： fei liao Xiaolei Yang State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China School of Engineering Sciences University of Chinese Academy of SciencesBeijing 100049China

The immersed boundary method has been widely used for simulating flows over complex ***,its accuracy in predicting the statistics of near-wall turbulence has not been fully *** this work,we evaluate the capability of the curvilinear immersed boundary(CURVIB)method in predicting near-wall velocity and pressure fluctuations in turbulent channel *** results show that quantities including the time-averaged streamwise velocity,the rms(root-mean-square)of velocity fluctuations,the rms of vorticity fluctuations,the shear stresses,and the correlation coefficients of u'and v"computed from the CURVIB simulations are in good agreement with those from the body-fitted *** importantly,it is found that the time-averaged pressure,the rms and wavenumber-frequency spectra of pressure fluctuations computed using the CURVIB method agree well with the body-fitted results.

关键词： Immersed boundary method Turbulent channel flow Wavenumber-frequency spectra Near-wall turbulence

Characteristics of Spatiotemporal Distribution of Sea Surface Wind along the East Coast of Guangdong Province

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Journal of Meteorological Research 2018年第4期32卷 627-635页

作者： fei liao Hua DENG Pak-wai CHAN Guangzhou Meteorological Observatory Guangzhou 511430 Guangzhou Institute of Tropical and Marine Meteorology China Meteorological AdministrationGuangzhou 510080 Guangdong Ecological Meteorology Center Guangzhou 510080 Hong Kong Observatory Hong Kong 999077

We analyzed the frequency distribution characteristics of wind speeds occurring at different offshore sites within a range of 0-200 km based on the sea surface wind data captured via buoys and oil platforms located along the east coast of Guangdong Province. The results of the analysis showed that average wind speed measured for each station reached a maximum in winter while minima occurred in summer, corresponding to obvious seasonal variation, and average wind speed increased with offshore distance. The prevailing wind direction at the nearshore site is the east-erly wind, and the frequency of winds within 6-10 m s^-1 is considerable with that of winds at 〉 10 m s^-1. With the in-crease of the offshore distance, the winds were less affected by the land, and the prevailing wind direction gradually became northerly winds, predominately those at 〉 10 m s^-1. For areas of shorter offshore distance （〈 100 km）, sur-face wind speeds fundamentally conformed to a two-parameter Weibull distribution, but there was a significant dif-ference between wind speed probability distributions and the Weibull distribution in areas more than 100 km off-shore. The mean wind speeds and wind speed standard deviations increased with the offshore distance, indicating that with the increase of the wind speed, the pulsation of the winds increased obviously, resulting in an increase in the ra-tio of the mean wind speed to the standard deviation of wind speed. When the ratio was large, the skewness became negative. When a relatively great degree of dispersion was noted between the observed skewness and the skewness corresponding to the theoretical Weibull curve, the wind speed probability distribution could not be adequately de-scribed by a Weibull distribution. This study provides a basis for the verification of the adaptability of Weibull distri-bution in different sea areas.

关键词： sea surface wind probability distribution observation buoy oil platform

The research on boundary layer evolution characteristics of Typhoon Usagi based on observations by wind profilers

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Acta Oceanologica Sinica 2017年第9期36卷 39-44页

作者： liao fei DENG Hua GAO Zhiqiu CHAN Pak-wai Guangzhou Meteorological Observatory Guangzhou 511430 China Guangzhou Institute of Tropical and Marine Meteorology China Meteorological Administration Guangzhou 510080 China Guangdong Ecological Meteorological Center Guangzhou 510080 China State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Hong Kong Observatory Hong Kong 999077 China

Vertically exploring the characteristics of the typhoon boundary layer（TBL） plays an important role in recognizing typhoon structure. The boundary layer radial direction and tangential wind characteristics of Typhoon Usagi based on the observational data of three boundary layer wind profiler stations along the route of Typhoon Usagi（No. 1319） and by combining with sounding data. The results show that：（1） maximum tangential wind appears in the vicinity of the eye area of Usagi, and it basically maintains a height of around 1 800 m when Usagi keeps a strong typhoon level, with the rapidly decreasing strength of Usagi after it lands, the speed of the maximum tangential wind and its vertical range both decrease;（2） the height of the maximum tangential wind is close to that of the inflow layer top of the typhoon, and is greater than that of the boundary layer estimated on the basis of Richardson number or potential temperature gradient, while the height of mixed layer judged on the basis of the signal-to-noise ratio（SNR） or its gradient is usually low;（3） the the boundary layer height can reach higher than2 100 m before Usagi lands. When the typhoon level or above is achieved, the boundary layer height observed by various stations does not change much, basically staying at between 1 200 and 1 600 m. With the decreasing strength of Usagi after its landfall, the boundary layer height rapidly drops.

关键词： typhoon boundary layer height wind profiler sounding

Effect of luteolin on apoptosis and vascular endothelial growth factor in human choroidal melanoma cells

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International Journal of Ophthalmology(English edition) 2021年第2期14卷 186-193页

作者： Meng-Lin Shi Yu-Fen Chen Hong-fei liao Nanchang University Nanchang 330000Jiangxi ProvinceChina Jiangxi Province Blood Center Nanchang 330052Jiangxi ProvinceChina Jiangxi Research Institute of Ophthalmology&Visual Sciences Nanchang 330000Jiangxi ProvinceChina Department of Ophthalmology the Affiliated Eye Hospital of Nanchang UniversityNanchang 330000Jiangxi ProvinceChina

AIM:To investigate the effects of luteolin on apoptosis,the cell cycle,and the expression and secretion of vascular endothelial growth factor(VEGF)in human choroidal melanoma cells(C918 and OCM-1).METHODS:C918 and OCM-1 cells cultured in vitro were treated with various concentrations of luteolin(0,5,10,15μmol/L).Cell growth was observed with an inverted microscope,and cell cycle arrest was detected by propidium iodide(PI)staining using flow *** was detected by Hoechst33342 staining,and apoptosis rate was determined by Annexin V-FITC/PI experiments using flow *** expression of apoptosis-related proteins Bcl-2,Bax and VEGF was analyzed using Western *** levels of VEGF secreted by the cells into the supernatant was analyzed using ***:After treating with 5 to 15μmol/L luteolin for 48 h,the fusion degree of C918 and OCM-1 cells decreased,and more floating apoptotic cells *** treatment increased the G0-G1 phase ratio of the C918 and OCM-1 cells,blocked cell cycle progression,and increased the apoptosis rate of the C918 and OCM-1 *** blot showed that luteolin decreased the expression of Bcl-2 and VEGF in the C918 and OCM-1 cells and increased the expression of Bax *** ELISA results showed that 10 to 15μmol/L luteolin decreased the cell secretion of ***:Luteolin may induce apoptosis by regulating the levels of apoptosis-related proteins in C918 and OCM-1 *** can induce cell cycle arrest,decrease the expression of VEGF.

关键词： luteolin human choroidal melanoma cells apoptosis cell cycle vascular endothelial growth factor

THE TEMPORAL AND SPATIAL DISTRIBUTION OF SEA SURFACE WIND ALONG THE COAST OF GUANGDONG PROVINCE IN CHINA

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Journal of Tropical Meteorology 2019年第1期25卷 129-140页

作者： liao fei DENG Hua CHAN Pak-wai Guangzhou Meteorological Observatory Guangzhou Institute of Tropical and Marine Meteorology CMA Guangdong Ecological Meteorology Center Hong Kong Observatory

Temporal and spatial distribution characteristics of sea surface wind in Guangdong's coastal areas were analyzed with data from four offshore observational stations between 2012 and 2015. The results are shown as follows:(1) The probability distribution of wind speed was basically consistent with Gaussian distribution characteristics; winds of Beaufort force 6 or higher were observed mainly in far offshore stations from October to March.(2) The probability distribution of wind direction was represented well by Weibull distribution. The deviation of wind direction of far station was relatively small for it was mainly controlled by monsoon over the South China Sea, while the near offshore station had a relatively large diurnal variation because of the influence of local synoptic systems such as sea-land breeze.(3) There were significant seasonal differences in wind speed and direction observed by different offshore observational stations. In strong wind seasons, the deviation of wind direction was relatively small while the deviation of wind speed was relatively large, and vice versa. In contrast with Class I station, the other three stations exhibited approximately normal distribution of wind direction and wind speed deviations.(4) Wind direction diurnal variation was moderate in windy periods, while it was obvious in relatively lower speed conditions. The deviation of wind speed in windy periods was generally greater because it was influenced by mesoscale weather systems for 10-20 h, and the influence was complicated, resulting in greater local differences in wind speed.

关键词： sea surface wind observation distribution characteristics

Iterative Model Predictive Control for Automatic Carrier Landing of Carrier-Based Aircrafts Under Complex Surroundings and Constraints

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Journal of Shanghai Jiaotong university(Science) 2024年第4期29卷 712-724页

作者： ZHANG Xiaotian HE Defeng liao fei College of Information Engineering Zhejiang University of TechnologyHangzhou310023China Aerospace Technology Institute China Aerodynamics Research and Development CenterMianyang621000SichuanChina

This paper considers the automatic carrier landing problem of carrier-based aircrafts subjected to constraints,deck motion,measurement noises,and unknown *** iterative model predictive control(MPC)strategy with constraints is proposed for automatic landing control of the ***,the long short-term memory(LSTM)neural network is used to calculate the adaptive reference trajectories of the *** the Sage-Husa adaptive Kalman filter and the disturbance observer are introduced to design the composite ***,an iterative optimization algorithm is presented to fast solve the receding horizon optimal control problem of MPC based on the Lagrange’s ***,some sufficient conditions are derived to guarantee the stability of the landing system in a closed loop with the ***,the simulation results of F/A-18A aircraft show that compared with the conventional MPC,the presented MPC strategy improves the computational efficiency by nearly 56%and satisfies the control performance requirements of carrier landing.

关键词： automatic carrier landing model predictive control(MPC) long short-term memory(LSTM)neural network stability computational efficiency

Clinical Features and Microvascular Complications Risk Factors of Early-onset Type 2 Diabetes Mellitus

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Current Medical Science 2019年第5期39卷 754-758页

作者： Jia-xin HUANG Yun-fei liao Yu-ming LI Department of Ultrasound Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430022China Department of Endocrinology Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430022China

The aim of this research was to study the clinical features and microvascular complications risk factors of early-onset type 2 diabetes mellitus(T2DM).We analyzed the clinical data from 1421 T2DM inpatients at Wuhan Union *** were divided into early-onset T2DM group(diagnostic age40 years).All subjects underwent a standardized assessment of microvascular *** were compared with independent-samples t test or Chi-square *** logistic regression was used to determine the risk factors of microvascular *** with early-onset T2DM were more inclined to have a lower systolic blood pressure(SBP),a longer duration of diabetes and higher levels of body mass index(BM1),uric acid(UA),fasting plasma glucose(FPG),total cholesterol(TC),triglyceride(TG)and glycosylated hemoglobin(HbAlc)than those with lateonset T2DM(P<0.05).The prevalence of diabetic retinopathy(DR)was significantly higher and that of diabetic peripheral neuropathy(DPN)was significantly lower in early-onset group than in late-onset group(P<0.05).For DN,UA was an independent risk factor in early-onset *** and TG were independent risk factors in late-onset *** DR,duration of diabetes and SBP were independent risk factors in early-onset *** of diabetes,SBP and HbAlc were independent risk factors in late-onset *** study demonstrated that the clinical characteristics of early-onset T2DM were metabolic disorders,including glucose metabolism,lipid metabolism and amino acid ***-onset T2DM was more likely to be associated with *** potential pathogenesis of early and late-onset T2DM might be *** management of metabolic risk factors especially HbA1c,SBP,TG and UA is advised to be performed in the early stage of diabetes.

关键词： early-onset type 2 diabetes mellitus diabetic microvascular complication diabetic nephropathy diabetic retinopathy diabetic peripheral neuropathy

A Survey of Non-Volatile Main Memory Technologies:State-of-the-Arts,Practices,and Future Directions

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Journal of Computer Science & Technology 2021年第1期36卷 4-32页

作者： Hai-Kun Liu Di Chen Hai Jin Xiao-fei liao Binsheng He Kan Hu Yu Zhang National Engineering Research Center for Big Data Technology and System Huazhong University of Science and TechnologyWuhan 430074China Services Computing Technology and System Laboratory Huazhong University of Science and Technology Wuhan 430074China Cluster and Grid Computing Laboratory Huazhong University of Science and TechnologyWuhan 430074China School of Computing Science and Technology Huazhong University of Science and TechnologyWuhan 430074China School of Computing National University of SingaporeSingapore 117418Singapore

Non-Volatile Main Memories (NVMMs) have recently emerged as a promising technology for future memory systems. Generally, NVMMs have many desirable properties such as high density, byte-addressability, non-volatility, low cost, and energy efficiency, at the expense of high write latency, high write power consumption, and limited write endurance. NVMMs have become a competitive alternative of Dynamic Random Access Memory (DRAM), and will fundamentally change the landscape of memory systems. They bring many research opportunities as well as challenges on system architectural designs, memory management in operating systems (OSes), and programming models for hybrid memory systems. In this article, we revisit the landscape of emerging NVMM technologies, and then survey the state-of-the-art studies of NVMM technologies. We classify those studies with a taxonomy according to different dimensions such as memory architectures, data persistence, performance improvement, energy saving, and wear leveling. Second, to demonstrate the best practices in building NVMM systems, we introduce our recent work of hybrid memory system designs from the dimensions of architectures, systems, and applications. At last, we present our vision of future research directions of NVMMs and shed some light on design challenges and opportunities.

关键词： non-volatile memory persistent memory hybrid memory systems memory hierarchy