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| 1 | Constrained large-eddy simulation and detached eddy simulation of flow past a commercial aircraft at 14 degrees angle of attack显示文摘With the development of computational power and numerical algorithms,computational fluid dynamics(CFD) has become an important strategy for the design of aircraft,which significantly reduces the reliance on wind-tunnel and flight tests.In this paper,we conducted a numerical investigation on the flow past a full commercial aircraft at Mach number 0.2 and 14 degrees angle of attack by means of Reynolds-averaged Navier-Stokes(RANS),detached-eddy simulation(DES) and our newly developed constrained large-eddy simulation(CLES).The objective of this paper is to study the capability of these models in simulating turbulent flows.To our knowledge,this is the first large-eddy simulation method for full commercial aircraft simulation.The results show that the CLES can predict the mean statistical quantities well,qualitatively consistent with traditional methods,and can capture more small-scale structures near the surface of the aircraft with massive separations.Our study demonstrates that CLES is a promising alternative for simulating real engineering turbulent flows. | CHEN ShiYi CHEN YingChun XIA ZhenHua QU Kun SHI YiPeng XIAO ZuoLi LIU QiuHong CAI QingDong LIU Feng LEE Cunbiao ZHANG RiKui CAI JinSheng | 2013 | Science China(Physics,Mechanics & Astronomy)2013，56，2： | 14 |
| 2 | The secretion profile of mesenchymal stem cells and potential applications in treating human diseases显示文摘Mesenchymal stromal/stem cells(MSCs)possess multi-lineage differentiation and self-renewal potentials.MSCs-based therapies have been widely utilized for the treatment of diverse inflammatory diseases,due to the potent immunoregulatory functions of MSCs.An increasing body of evidence indicates that MSCs exert their therapeutic effects largely through their paracrine actions.Growth factors,cytokines,chemokines,extracellular matrix components,and metabolic products were all found to be functional molecules of MSCs in various therapeutic paradigms.These secretory factors contribute to immune modulation,tissue remodeling,and cellular homeostasis during regeneration.In this review,we summarize and discuss recent advances in our understanding of the secretory behavior of MSCs and the intracellular communication that accounts for their potential in treating human diseases. | Yuyi Han Jianxin Yang Jiankai Fang Yipeng Zhou Eleonora Candi Jihong Wang Dong Hua Changshun Shao Yufang Shi | 2022 | Signal Transduction and Targeted Therapy2022，7，4： | 6 |
| 3 | Numerical investigation of plane Couette flow with weak spanwise rotation显示文摘Direct numerical simulation of rotating plane Couette flow(RPCF) at Re_w= 1300 and Ro = 0.02 was performed with different mesh resolutions and different sizes of computation domain. Our results showed that a grid resolution in wall units with ?x^+=8.51, ?z^+= 4.26, ?y^+|_(min)= 0.0873 and ?y^+|_(max)= 3.89 is fine enough to simulate the problem at the present parameters. The streamwise length Lxand spanwise length Lzof the computational box have different impacts on the flow statistics, where the statistics were converged if Lxis longer than 8πh, while no converged results were obtained for different Lz. More importantly,our results with very long simulation time showed that a state transition would happen if L_x≥ 8πh, from a state with four pairs of roll cells to a state with three pairs of roll cells with L_z= 6πh. Each state could survive for more than 1500 h/U_w, and the flow statistics were different. | YuHan Huang ZhenHua Xia MinPing Wan YiPeng Shi ShiYi Chen | 2019 | Science China(Physics,Mechanics & Astronomy)2019，62，4： | 2 |
| 4 | Orbital-regulated interfacial electronic coupling endows Ni3N with superior catalytic surface for hydrogen evolution reaction显示文摘The interstitial structure and weak Ni-N interaction of Ni3N lead to high unoccupied d orbital energy and unsuitable orbital orientation,which consequently results in weak orbital coupling with H2O and slow water dissociation kinetics for alkaline hydrogen evolution catalysis.Herein,we successfully lower the unoccupied d orbital energy of Ni3N to strengthen the interfacial electronic coupling by employing the strong electron pulling capability of oxygen dopants.The prepared O-Ni3N catalyst delivers an overpotential of 55 mV at 10 mA cm−2,very close to the commercial Pt/C.Refined structural characterization indicates the oxygen incorporation can decrease the electron densities around the Ni sites.Moreover,density functional theory calculation further proves the oxygen incorporation can create more unoccupied orbitals with lower energy and superior orientation for water adsorption and dissociation.The concept of orbital-regulated interfacial electronic coupling could offer a unique approach for the rational design of hydrogen evolution catalysts and beyond. | Yanyan Fang Da Sun Shuwen Niu Jinyan Cai Yipeng Zang Yishang Wu Linqin Zhu Yufang Xie Yun Liu Zixuan Zhu Amirabbas Mosallanezhad Di Niu Zheng Lu Junjie Shi Xiaojing Liu Dewei Rao Gongming Wang Yitai Qian | 2020 | Science China Chemistry2020，63，11： | 1 |
| 5 | On the governing equations for the compressing process and its coupling with other processes显示文摘As a continuation of a recent linear analysis by Mao et al.(Acta Mech Sin,2010,26:355),in this paper we propose a general theoretical formulation for the compressing process in complex Newtonian fluid flows,which covers gas dynamics,aeroacoustics,nonlinear thermoviscous acoustics,viscous shock layer,etc.,as its special branches.The principle on which our formulation is based is the maximally natural and dynamic Helmholtz decomposition of the Navier-Stokes equation,along with the kinematic Helmholtz decomposition of the velocity field.The central results are the new dilatation equation and velocity-potential equation,which are the counterparts of vorticity transport equation and vector stream-function equation for the shearing process,respectively.Various couplings of the compressing process with shearing and thermal processes,including its physical sources,are carefully identified.While the possible applications and influences of the new formulation are yet to be explored,our preliminary discussion on the pros and cons of previous formulations pertain to acoustic analogy and that on the process splitting and coupling in highly compressible turbulence indicates that at least the formulation can serve as a new frame of reference by which one may gain some additional insight and thereby develop new approaches to the multi-process complex flow problems. | MAO Feng SHI YiPeng XUAN LiJun SU WeiDong WU JieZhi | 2011 | Science China(Physics,Mechanics & Astronomy)2011，54，6： | 1 |
| 6 | Identifying pathogenicity genes in the rubber tree anthracnose fungus Colletotrichum gloeosporioides through random insertional mutagenesis显示文摘 | Zhiying Cai Guohua Li Chunhua Lin Tao Shi Ligang Zhai Yipeng Chen Guixiu Huang | 2013 | Microbiological Research2013，，6： | 1 |
| 7 | Numerical simulation of cavitating flow around a slender body with slip boundary condition显示文摘In this paper, we perform a numerical simulation of the cavitating flow around an underwater hemispherical-head slender body running at a high speed. For the first time, the slip boundary condition is introduced into this problem, and we find that the slip boundary condition has a big influence on the cavitation in the flow-separation zone. By simulating the cavitating flow under different cavitation numbers, we demonstrate that the slip boundary condition can effectively reduce the intensity of cavitation, as represented by the length of cavitation bubbles. The present paper provides a new method for utilization of new surface materials to control the cavitation on the underwater moving objects. | Hao Liu DanDan Li YaHui Xue PengYu Lu YiPeng Shi HuiLing Duan | 2016 | Science China(Physics,Mechanics & Astronomy)2016，59，2： | 0 |
| 8 | Effect of Oscillation Structures on Inertial-Range Intermittence and Topology in Turbulent Field显示文摘Using the incompressible isotropic turbulent fields obtained from direct numerical simulation and large-eddy simulation,we studied the statistics of oscillation structures based on local zero-crossings and their relation with inertial-range intermittency for transverse velocity and passive scalar.Our results show that for both the velocity and passive scalar,the local oscillation structures are statistically scaleinvariant at high Reynolds number,and the inertial-range intermittency of the overall flow region is determined by the most intermittent structures characterized by one local zero-crossing.Local flow patterns conditioned on the oscillation structures are characterized by the joint probability density function of the invariants of the filtered velocity gradient tensor at inertial range.We demonstrate that the most intermittent regions for longitudinal velocity tend to lay at the saddle area,while those for the transverse velocity tend to locate at the vortex-dominated area.The connection between the ramp-cliff structures in passive scalar field and the corresponding saddle regions in the velocity field is also verified by the approach of oscillation structure classification. | Kun Yang Zhenhua Xia Yipeng Shi Shiyi Chen | 2016 | Communications in Computational Physics2016，19，1： | 0 |
| 9 | TiO_(2) nanofiber-supported copper nanoparticle catalysts for highly efficient methane conversion to C1 oxygenates under mild conditions显示文摘The selective oxidation of methane under mild conditions remains the“Holy Grail of Catalysis”.The key to activating methane and inhibiting over-oxidation of target oxygenates lies in designing active centers.Copper nanoparticles were loaded onto TiO_(2) nanofibers using the photo-deposition method.The resulting catalysts were found to effectively convert methane into C1 oxygenated products under mild conditions.Compared with previously reported catalysts,it delivers a superior performance of up to 2510.7 mmol·g_(Cu)^(-1)·h^(-1) productivity with a selectivity of around 100%at 80℃for 5 min.Microstructure characterizations and density functional theory(DFT)calculations indicate that TiO_(2) in the mixed phase of anatase and rutile significantly increases the Cu^(+)/CuO ratio of the supported Cu species,and this ratio is linearly related to the formation rate of oxygen-containing species.The CuI site promotes the generation of active O species from H_(2)O_(2) dissociation on Cu_(2)O(111).These active O species reduce the energy barrier for breaking the C-H bond of CH_(4),thus boosting the catalytic activity.The methane conversion mechanism was proposed as a methyl radical pathway to form CH_(3)OH and CH_(3)OOH,and then the generated CH_(3)OH is further oxidized to HOCH_(2)OOH. | Wencui Li Yu Ren Zean Xie Yipeng Wang Hang Zhang Dianxiang Peng Hengfang Shen Hongfei Shi Jiaxin Cai Peng Wang Tongxin Zhang Zhen Zhao | 2024 | Nano Research2024，17，5： | 0 |
| 10 | DYNAMICS OF RELATIVISTIC FLUID FOR COMPRESSIBLE GAS显示文摘In this paper the relativistic fluid dynamics for compressible gas is studied.We show that the strict convexity of the negative thermodynamical entropy preserves invariant under the Lorentz transformation if and only if the local speed of sound in this gas is strictly less than that of light in the vacuum.A symmetric form for the equations of relativistic hydrodynamics is presented,and thus the local classical solutions to these equations can be deduced.At last,the non-relativistic limits of these local classical solutions are showed to be the classical solutions to the Euler equations for polytropic gas. | Yipeng Shi (State Key Laboratory for Turbulence and Complex Systems,College of Engineering,Peking University,Beijing 100871) Qiyan Shi (Dept.of Math.,Fuzhou University,Fuzhou 350108) | 2011 | Annals of Differential Equations2011，27，4： | 0 |
| 11 | Constrained Large-Eddy Simulation of Compressible Flow Past a Circular Cylinder显示文摘Compressible flow past a circular cylinder at an inflow Reynolds number of 2×105 is numerically investigated by using a constrained large-eddy simulation(CLES)technique.Numerical simulation with adiabatic wall boundary condition and at a free-stream Mach number of 0.75 is conducted to validate and verify the performance of the present CLES method in predicting separated flows.Some typical and characteristic physical quantities,such as the drag coefficient,the root-mean-square lift fluctuations,the Strouhal number,the pressure and skin friction distributions around the cylinder,etc.are calculated and compared with previously reported experimental data,finer-grid large-eddy simulation(LES)data and those obtained in the present LES and detached-eddy simulation(DES)on coarse grids.It turns out that CLES is superior to DES in predicting such separated flow and that CLES can mimic the intricate shock wave dynamics quite well.Then,the effects of Mach number on the flow patterns and parameters such as the pressure,skin friction and drag coefficients,and the cylinder surface temperature are studied,with Mach number varying from 0.1 to 0.95.Nonmonotonic behaviors of the pressure and skin friction distributions are observed with increasing Mach number and the minimum mean separation angle occurs at a subcritical Mach number of between 0.3 and 0.5.Additionally,the wall temperature effects on the thermodynamic and aerodynamic quantities are explored in a series of simulations using isothermal wall boundary conditions at three different wall temperatures.It is found that the flow separates earlier from the cylinder surface with a longer recirculation length in the wake and a higher pressure coefficient at the rear stagnation point for higher wall temperature.Moreover,the influences of different thermal wall boundary conditions on the flow field are gradually magnified from the front stagnation point to the rear stagnation point.It is inferred that the CLES approach in its current version is a useful and effective tool for simulating wall-bounded compressible turbulent flows with massive separations. | Renkai Hong Zhenhua Xia Yipeng Shi Zuoli Xiao Shiyi Chen | 2014 | Communications in Computational Physics2014，15，2： | 0 |
| 12 | Dissipation function in turbulent plane Poiseuille and Couette flows subject to spanwise rotations显示文摘The dissipation function in turbulent plane Poiseuille flows(PPFs) and plane Couette flows(PCFs) subject to spanwise rotations is analyzed. It is found that, in the PCFs without system rotations, the mean part is constant while the fluctuation part follows a logarithmic law, resulting in a similar logarithmic skin friction law as PPFs.However, if the flow system rotates in the spanwise direction, no obvious dependence on the rotation number can be evaluated. In the PPFs with rotations, the dissipation function shows an increase with the rotation number, while in the PCFs with rotations,when the rotation number increases, the dissipation function first decreases and then increases. | Zhenhua XIA Yipeng SHI Qingdong CAI Jie GAI | 2019 | Applied Mathematics and Mechanics(English Edition)2019，40，2： | 0 |
| 13 | Causal mechanism behind the stall delay by airfoil's pitching-up motion显示文摘Why the stall of an airfoil can be significantly delayed by its pitching-up motion? Various attempts have been proposed to answer this question over the past half century, but none is satisfactory. In this letter we prove that a chain of vorticity-dynamics processes at accelerating boundary is fully responsible for the causal mechanism underlying this peculiar phenomenon. The local flow behavior is explained by a simple potential-flow model. | Shufan Zou Ankang Gao Yipeng Shi Jiezhi Wu | 2017 | Theoretical & Applied Mechanics Letters2017，7，5： | 0 |
| 14 | A Hybrid Numerical Simulation of Supersonic IsotropicTurbulence显示文摘This paper presents an extension work of the hybrid scheme proposed by Wang et al.[J.Comput.Phys.229(2010)169-180]for numerical simulation of sub-sonic isotropic turbulence to supersonic turbulence regime.The scheme still utilizes an 8th-order compact scheme with built-in hyperviscosity for smooth regions and a 7th-order WENO scheme for highly compression regions,but now both in their con-servation formulations and for the latter with the Roe type characteristic-wise recon-struction.To enhance the robustness of the WENO scheme without compromising its high-resolution and accuracy,the recursive-order-reduction procedure is adopted,where a new type of reconstruction-failure-detection criterion is constructed from the idea of positivity-preserving.In addition,a new form of cooling function is proposed,which is proved also to be positivity-preserving.With a combination of these techniques,the new scheme not only inherits the good properties of the original one but also extends largely the computable range of turbulent Mach number,which has been further confirmed by numerical results. | Luoqin Liu Jianchun Wang Yipeng Shi Shiyi Chen X.T.He | 2019 | Communications in Computational Physics2019，25，1： | 0 |
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