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1,061 results on '"Lv, Yu"'

3. Large-eddy simulation of separated flows on unconventionally coarse grids

Author

Bin, Yuanwei, Park, George I., Lv, Yu, and Yang, Xiang I. A.

Subjects
Physics - Fluid Dynamics
Abstract

We examine and benchmark the emerging idea of applying the large-eddy simulation (LES) formalism to unconventionally coarse grids where RANS would be considered more appropriate at first glance. We distinguish this idea from very-large-eddy-simulation (VLES) and detached-eddy-simulation (DES), which require switching between RANS and LES formalism. LES on RANS grid is appealing because first, it requires minimal changes to a production code; second, it is more cost-effective than LES; third, it converges to LES; and most importantly, it accurately predicts flows with separation. This work quantifies the benefit of LES on RANS-like grids as compared to RANS on the same grids. Three canonical cases are considered: periodic hill, backward-facing step, and jet in cross flow. We conduct direct numerical simulation (DNS), proper LES on LES grids, LES on RANS-quality grids, and RANS. We show that while the LES solutions on the RANS-quality grids are not grid converged, they are twice as accurate as the RANS on the same grids.

Published
2023

5. Time Synchronized Sensor Network with IEEE1588 for Vibration Measurement in Structural Health Monitoring of Railway System

Author

Jiang, Guotao, Liu, Yong, lv, Yu, Wu, Haiyan, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Zhang, Junjie James, Series Editor, Tan, Kay Chen, Series Editor, Gong, Ming, editor, Yang, Jianwei, editor, Liu, Zhigang, editor, and An, Min, editor

Published
2024
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27. LES wall modeling for heat transfer at high speeds

Author

Chen, Peng E. S., Lv, Yu, Xu, Haosen H. A., Shi, Yipeng, and Yang, Xiang I. A.

Subjects
Physics - Fluid Dynamics
Abstract

A practical application of universal wall scalings is near-wall turbulence modeling. In this paper, we exploit temperature's semi-local scaling [Patel, Boersma, and Pecnik, {Scalar statistics in variable property turbulent channel flows}, Phys. Rev. Fluids, 2017, 2(8), 084604] and derive an eddy conductivity closure for wall-modeled large-eddy simulation of high-speed flows. We show that while the semi-local scaling does not collapse high-speed direct numerical simulation (DNS) data, the resulting eddy conductivity and the wall model work fairly well. The paper attempts to answer the following outstanding question: why the semi-local scaling fails but the resulting eddy conductivity works well. We conduct DNSs of Couette flows at Mach numbers from $M=1.4$ to 6. We add a source term in the energy equation to get a cold, a close-to-adiabatic wall, and a hot wall. Detailed analysis of the flows' energy budgets shows that aerodynamic heating is the answer to our question: aerodynamic heating is not accounted for in Patel et al.'s semi-local scaling but is modeled in the equilibrium wall model. We incorporate aerodynamic heating in semi-local scaling and show that the new scaling successfully collapses the high-speed DNS data. We also show that incorporating aerodynamic heating or not, the semi-local scaling gives rise to the exact same eddy conductivity, thereby answering the outstanding question., Comment: 24 pages, 13 figures

Published
2021

31. Economic burden attributable to healthcare-associated infections at western China hospitals: 6 Year, prospective cohort study

Author

Lv, Yu, Huang, Xiaobo, Wu, Jiayu, Xiao, Xueqin, Ma, Chunhua, Jiang, Xiaoyun, Zhou, Ping, Liu, Linlin, Jiang, Yiguo, Zou, Anna, Niu, Hui, Sun, Juhua, Hou, Li, Wang, Xiaomeng, Dai, Yulin, Peng, Shuling, Deng, Xiaorong, Xia, Hong, Guo, Yao, Wang, Defen, Huang, Ting, Li, Chunyu, He, Lirong, Xiong, Fengqing, Xiong, Hongmei, Cao, Hongmei, Lu, Jie, Liu, Xingfeng, Jian, Xiaohong, Luo, Wanzhen, An, Yanmei, Wu, Yumei, Deng, Keqin, Kang, Xiaoli, Chen, Xiaorong, Tang, Beibei, Li, Li, and Xiang, Qian

Published
2024
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42. 16p11.2 CNV gene Doc2α functions in neurodevelopment and social behaviors through interaction with Secretagogin

Author

Qiu-Wen Wang, Junhong Qin, Yan-Fen Chen, Yingfeng Tu, Yun-Yun Xing, Yuchen Wang, Lv-Yu Yang, Si-Yao Lu, Libo Geng, Wei Shi, Yiming Yang, and Jun Yao

Subjects
CP: Neuroscience, CP: Developmental biology, Biology (General), QH301-705.5
Abstract

Summary: Copy-number variations (CNVs) of the human 16p11.2 genetic locus are associated with neurodevelopmental disorders, including autism spectrum disorders (ASDs) and schizophrenia. However, it remains largely unclear how this locus is involved in the disease pathogenesis. Doc2α is localized within this locus. Here, using in vivo and ex vivo electrophysiological and morphological approaches, we show that Doc2α-deficient mice have neuronal morphological abnormalities and defects in neural activity. Moreover, the Doc2α-deficient mice exhibit social and repetitive behavioral deficits. Furthermore, we demonstrate that Doc2α functions in behavioral and neural phenotypes through interaction with Secretagogin (SCGN). Finally, we demonstrate that SCGN functions in social/repetitive behaviors, glutamate release, and neuronal morphology of the mice through its Doc2α-interacting activity. Therefore, Doc2α likely contributes to neurodevelopmental disorders through its interaction with SCGN.

Published
2023
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50. Lyapunov exponent and Wasserstein metric as validation tools for assessing short-time dynamics and quantitative model evaluation of large-eddy simulation

Author

Wu, Hao, Ma, Peter C., Lv, Yu, and Ihme, Matthias

Subjects
Physics - Fluid Dynamics
Abstract

In this work, methods for the evaluation of LES-quality and LES-accuracy are presented, which include the Lyapunov exponent for the analysis of short-time predictability of LES-calculation and the Wasserstein metric for the quantitative assessment of simulation results. Both methods are derived and evaluated in application to the Volvo test case. Both the non-reacting and reacting cases are calculated. For the non- reacting cases, good agreement with the experimental data is achieved by solvers at high numerical resolution. The reacting cases are more challenging due to the small length scale of the flame and the suppression of sinuous mode of absolute instability by the density ratio. The analysis of the turbulent simulation data using the concept of the Lyapunov exponent and the Wasserstein metric provides a more quantitative approach to assess the mesh dependency of the simulation results. The convergence of the Lyapunov exponent is shown to be a more sensitive and stronger indication of mesh-independence. Though grid convergence for the reacting cases cannot be reached with the chosen resolutions, the Lyapunov exponents and the Wasserstein metric are shown to be capable of identifying quantity-specific sensitivities with respect to the numerical resolution, while requiring significantly less computational resources than acquiring profiles of conventional turbulent statistics., Comment: 2018 AIAA Aerospace Sciences Meeting, Kissimmee, FL

Published
2018

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