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Analysis on nasal airway by using scale-adaptive simulation combined with standard κ-ω model and 3D printing modeling physical experiment

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Theoretical & Applied Mechanics Letters 2019年第4期9卷 215-219,I0006页

作者： jiemin zhan Yangyang Xi Kay Lin Weiguang Yu Wenqing Hu Department of Applied Mechanics Sun Yat-sen University

The physiological structure of the upper respiratory tract is complex and varies with each individual,and the circulating air has turbulent *** this paper,based on computed tomography(CT)medical images published online and the three-dimensional(3D)printing technology,a 3D model of the human upper respiratory tract was reconstructed and an experimental device of the upper respiratory tract was *** implemented the respiratory experiment and measured the flow rate,and a scale-adaptive κ-ω model is applied for numerical simulation,the results are in good *** flow field during respiratory was analyzed by coronal velocity cross section,vortex line and particle *** found that the relatively strong shear effect happens at the areas of nasal valve and *** the middle and upper nasal tract,vortex line separation occurs and there is significant passage *** results indicate that SAS method is effective in studying upper respiratory airflow.

关键词： 3D printer Scale-adaptive simulation Upper respiratory tract Physical experiment

Three-Dimensional 　Modelling　for　Natural　Synovial　Joints

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Communications in Nonlinear Science and Numerical Simulation 1997年第2期2卷 69-71页

作者： Jiehui zhan, Yaosong CHEN & jiemin zhan (Affiliated Hosptial of Traumatology, Guangzhou University of Traditional Chinese Medicine, Jiang Nan Westroad, Guangzhou, P.R.China) (Department of Mechanics, Peking University, Beijing, P.R.China) (department Affiliated Hospital of Traumatology Guangzhou Univ. Traditional C.M. Guangzhou Jiang Nan Westroad China Department of Mechanics Peking University Beijing 100871 China Dept. of Appl. Mechanics and Eng. Zhongshan University Guangzhou China

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关键词： lubrication natural synovial joint 3-D numerical model FDM

An Experimental Set-Up for the in Vitro Simulation of a Physiological Pulsatile Flow in the Abdominal Aorta

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Journal of Flow Control, Measurement & Visualization 2022年第4期10卷 148-160页

作者： Tiandong Lu jiemin zhan Wei Su Wenqing Hu Department of Applied Mechanics and Engineering School of Aeronautics and Astronautics Sun Yat-sen University Guangzhou China

In vitro experimental set-up is an important tool for investigating abdominal aortic aneurysm (AAA). Accurate reproduction of the physiological pulsatile flow waveform in the abdominal aorta at various anatomic locations is an important component of these experimental methods. The objective of this study is to establish an experimental set-up to generate a physiological pulsatile flow for in vitro simulations of the abdominal aorta. The physiological flow was established by a computer-controlled peristaltic pump and the flow field in a circular straight pipe is measured under pulsatile flow conditions by a 2-dimensional particle image velocimetry system (2D-PIV). Experimental results show that the in vitro experimental set-up provides a flow with a period of 2 s, a reasonable cross-sectional velocity distribution and an approximate inlet velocity profile that is close to the human abdominal aorta.

关键词： 2-Dimensional Particle Image Velocimetry System Abdominal Aorta Blood-Flow Experimental Set-Up Flow Field

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波浪破碎的一种混合湍流模拟模式

力学学报 2019年第6期51卷 1712-1719页

作者：詹杰民李熠华中山大学应用力学与工程系

近岸波浪的变形与破碎,一方面影响水体与泥沙运输,另一方面对消波护岸具有指导意义.本文提出一种三维混合湍流模拟模式方法,将求解区域分为造波区、波浪传播区和消波区.造波区采用层流模式,通过基于Fluent的二次开发的UDF方法在边界进... 详细信息

近岸波浪的变形与破碎,一方面影响水体与泥沙运输,另一方面对消波护岸具有指导意义.本文提出一种三维混合湍流模拟模式方法,将求解区域分为造波区、波浪传播区和消波区.造波区采用层流模式,通过基于Fluent的二次开发的UDF方法在边界进行速度造波.这种方法在给定入口速度的条件下,根据已知波高进行精准插值,从而控制水的体积分数.在波浪传播区域,采用大涡模拟进行模拟研究,在消波区,采用RANS模型并利用多孔介质消波法进行消波.模型通过VOF方法捕捉波浪破碎过程中的自由面变化.本文对波高为5.5 cm的规则波(M1)、波高为13.5cm的规则波(M3)、有效波高为7.75cm的TMA谱单向不规则波(U1)和有效波高为19cm的TMA谱多向不规则波(B5)展开了模拟研究,并与前人的相关实验结果作比较,各条件下模拟结果与实验结果吻合.模拟结果说明本文提出的模型能够准确模拟出波浪传播过程中的折射和绕射现象,并且能够捕捉的波浪破碎过程中的自由面变化,为三维波浪的传播与破碎的数值模拟提供一种模拟方法.

关键词：波浪破碎湍流数值模拟混合模式大涡模拟

Numerical investigation of air-entrainment in skimming flow over stepped spillways

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Theoretical & Applied Mechanics Letters 2016年第3期6卷 139-142页

作者： jiemin zhan Jianbo zhang Yejun Gong Department of Applied Mechanics and Engineering School of Engineering Sun Yat-sen University

As a widely used flood energy dissipator, the stepped spillway can significantly dissipate the kinetic or hydraulic energy due to the air-entrainment in skimming flow over the steps. The free-surface aeration involves the sharp deformation of the free surface and the complex turbulent shear flows. In this study, the volume of fluid （VOF）, mixture, and Eulerian methods are utilized to simulate the air-entrainment by coupling with the Reynolds-averaged Navier-Stokes/large eddy simulation （RANS/LES） turbulence models. The free surface deformation, air volume fraction, pressure, and velocity are compared for the three different numerical methods. Only the Eulerian＋RANS method fails to capture the free-surface aeration. The air volume fraction predicted by the VOF＋LES method best matches the experimental measurement, while the mixture＋LES method predicts the inception point of the air entrainment more accurately.

关键词： Skimming flow Stepped spillways Air-entrainment Large eddy simulation

Large Eddy Simulations of Rayleigh-Bénard Convection in a Cubic Cavity

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Open Journal of Fluid Dynamics 2023年第3期13卷 177-190页

作者： Tian Qin Yingying Luo jiemin zhan Wenqing Hu Yutian Li Ziwei Huang Department of Applied Mechanics and Engineering School of Aeronautics and Astronautics Shenzhen Campus of Sun Yat-sen University Shenzhen China

This paper conducts a Large Eddy Simulation (LES) of Rayleigh Bénard convection in a cubic cavity based on the WMLES S-Omega subgrid-scale model. For a cubic cavity with a vertical temperature difference of 6.7°C and 20°C, the velocity pulsation profiles and the mean velocity profiles of the vertical section in the middle of the cubic cavity were simulated, respectively. And they are consistent with the experiment results. Furthermore, the mean velocity field of the vertical cross-section in the middle of the cavity was calculated. Structures of the mean velocity field in the two cases are similar. A counterclockwise large vortex is found to occupy the cavity, and there are two small clockwise vortices in the lower left and upper right corners, and the mean velocity fields at two different temperature differences are consistent with the experimental results. The two-dimensional instantaneous temperature field and mean temperature field with different cross-sections in the z-direction, as well as the three-dimensional instantaneous isothermal surface structure, indicate that the large-scale circulation motion within the cubic cavity is moving diagonally. In addition, the structure of the mean streamline also illustrates this viewpoint. For the reverse vortex formed at two corners in the mean streamline structure, we used the Q criterion to identify and obtain two vortex structures similar to boomerangs. The basic turbulent structure in RB thermal convection includes the rising and falling plumes generated by buoyancy effects.

关键词： Large Eddy Simulation Rayleigh-Bénard Convection Cubic Cavity Plume Flow

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Fortran与***的混合编程

中山大学学报（自然科学版） 2017年第4期56卷 1-8页

作者：胡文清詹杰民中山大学工学院应用力学与工程系广东广州510275

Fortran语言具有很高的执行效率,广泛地应用于数值计算领域,积累了大量高效可靠的源程序,例如,Microsoft公司的IMSL Fortran程序库,为科学计算提供了强大的工具。***是完全面向对象的语言,与VB相比,***具有快速简易地开发功能更强大的Wi... 详细信息

Fortran语言具有很高的执行效率,广泛地应用于数值计算领域,积累了大量高效可靠的源程序,例如,Microsoft公司的IMSL Fortran程序库,为科学计算提供了强大的工具。***是完全面向对象的语言,与VB相比,***具有快速简易地开发功能更强大的Windows程序的优点。剖析了***通过动态链接库模式调用Fortran的混合编程,针对变量、字符串、数组、结构体、结构体数组等情况给出对应的调用方法,并给出了典型示例。为开发集合Fortran和***优点,兼具高执行效率和快速简易开发能力的软件提供技术支持。

关键词： Fortran *** 混合编程

一种在Fluent UDF中使用IMSL Fortran数值库的方法

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中山大学学报（自然科学版） 2017年第3期56卷 31-35页

作者：胡文清詹杰民中山大学工学院应用力学与工程系广东广州510275

UDF能极大地延伸Fluent的功能,被广泛应用于Fluent的各类计算中。IMSL是一个集合数学与统计函数的程序库,具有高效率、性能强大、应用简单等优点。研究并找到了一种方法,通过将调用IMSL的Fortran程序编译为动态链接库,并在UDF中调用该... 详细信息

UDF能极大地延伸Fluent的功能,被广泛应用于Fluent的各类计算中。IMSL是一个集合数学与统计函数的程序库,具有高效率、性能强大、应用简单等优点。研究并找到了一种方法,通过将调用IMSL的Fortran程序编译为动态链接库,并在UDF中调用该动态链接库,实现在UDF中使用IMSL数值库;同时给出了一个实例,在数值水槽中生成椭圆余弦波。为结合IMSL的优点,实现更简单、更快速、更自然的UDF程序编写提供了技术支持,极大地提高了复杂UDF的编写能力,增强Fluent的计算能力和应用范围。

关键词： Fluent UDF IMSL Fortran 椭圆余弦波

Preliminary Model Study for Forecasting a Hot Weather Process in Guangdong Province Using CMA-TRAMS

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Atmospheric and Climate Sciences 2024年第1期14卷 101-117页

作者： Wenfan Wang jiemin zhan Dehui Chen Zitong Chen Yanxia zhang Qing Fan Guangfeng Dai Yingying Luo Aifen Ye Department of Applied Mechanics and Engineering Shenzhen Campus of Sun Yat-sen University Shenzhen Guangdong China Guangzhou Institute of Tropical and Marine Meteorology/Guangdong Provincial Key Laboratory of Regional Numerical Weather Prediction CMA Guangzhou China

In this paper, the CMA-TRAMS tropical high-resolution system was used to forecast a typical hot weather process in Guangdong, China with different horizontal resolutions and surface coverage. The results of resolutions of 0.02° and 0.06° were presented with the same surface coverage of the GlobeLand30 V2020, companies with the results of resolution 0.02° with the USGS global surface coverage. The results showed that, on the overall assessment the 2 km model performed better in forecasting 2 m temperature, while the 6 km model was more accurate in predicting 10 m wind speed. In the evaluation of representative stations, the 2 km model performed better in forecasting 2 m temperature and 2 m relative humidity at the coastal stations, and the 2 km model was also better in forecasting 2 m pressure at the representative stations. However, the 6 km model performed better in forecasting 10 m wind speed at the representative stations. Furthermore, the 2 km model, owing to its higher horizontal resolution, presented a more detailed stratification of various meteorological field maps, allowing for a more pronounced simulation of local meteorological element variations. And the use of the surface coverage data of the GlobeLand30 V2020 improved the forecasting of 2 m temperature, and 10 m wind speed compared to the USGS surface coverage data.

关键词： High-Resolution Numerical Model CMA-TRAMS Model Test Evaluation Surface Coverage Numerical Simulation