A hybrid numerical simulation method for typhoon wind field over complex terrain

Huang, Wenfeng,Zhou, Huanlin Techno-Press 2014 Wind and Structures, An International Journal (WAS Vol.18 No.5

In spite of progress in the numerical simulation of typhoon wind field in atmospheric boundary layer (ABL), using typhoon wind field model in conjunction with Monte Carlo simulation method can only accurately evaluate typhoon wind field over a general terrain. This method is not enough for a reliable evaluation of typhoon wind field over the actual complex terrain with surface roughness and topography variations. To predict typhoon wind field over the actual complex terrain in ABL, a hybrid numerical simulation method combined typhoon simulation used the typhoon wind field model proposed by Meng et al. (1995) and CFD simulation in which the Reynolds averaged Navier-Stokes (RANS) equations and k-${\varepsilon}$ turbulence model are used. Typhoon wind filed during typhoon Dujuan and Imbudo are simulated using the hybrid numerical simulation method, and compared with the results predicted by the typhoon wind field model and the wind field measurement data collected by Fugro Geotechnical Services (FGS) in Hong Kong at the bridge site from the field monitoring system of wind turbulence parameters (FMS-WTP) to validate the feasibility and accuracy of the hybrid numerical simulation method. The comparison demonstrates that the hybrid numerical simulation method gives more accurate prediction to typhoon wind speed and direction, because the effect of topography is taken into account in the hybrid numerical simulation method.

A hybrid numerical simulation method for typhoon wind field over complex terrain

Wenfeng Huang,Huanlin Zhou 한국풍공학회 2014 Wind and Structures, An International Journal (WAS Vol.18 No.5

In spite of progress in the numerical simulation of typhoon wind field in atmospheric boundary layer (ABL), using typhoon wind field model in conjunction with Monte Carlo simulation method can only accurately evaluate typhoon wind field over a general terrain. This method is not enough for a reliable evaluation of typhoon wind field over the actual complex terrain with surface roughness and topography variations. To predict typhoon wind field over the actual complex terrain in ABL, a hybrid numerical simulation method combined typhoon simulation used the typhoon wind field model proposed by Meng et al. (1995) and CFD simulation in which the Reynolds averaged Navier-Stokes (RANS) equations and k-e turbulence model are used. Typhoon wind filed during typhoon Dujuan and Imbudo are simulated using the hybrid numerical simulation method, and compared with the results predicted by the typhoon wind field model and the wind field measurement data collected by Fugro Geotechnical Services (FGS) in Hong Kong at the bridge site from the field monitoring system of wind turbulence parameters (FMS-WTP) to validate the feasibility and accuracy of the hybrid numerical simulation method. The comparison demonstrates that the hybrid numerical simulation method gives more accurate prediction to typhoon wind speed and direction, because the effect of topography is taken into account in the hybrid numerical simulation method.

Wind field simulation over complex terrain under different inflow wind directions

Wenfeng Huang,Xibin Zhang 한국풍공학회 2019 Wind and Structures, An International Journal (WAS Vol.28 No.4

Accurate numerical simulation of wind field over complex terrain is an important prerequisite for wind resource assessment. In this study, numerical simulation of wind field over complex terrain was further carried out by taking the complex terrain around Siu Ho Wan station in Hong Kong as an example. By artificially expanding the original digital model data, Gambit and ICEM CFD software were used to create high-precision complex terrain model with high-quality meshing. The equilibrium atmospheric boundary layer simulation based on RANS turbulence model was carried out in a flat terrain domain, and the approximate inflow boundary conditions for the wind field simulation over complex terrain were established. Based on this, numerical simulations of wind field over complex terrain under different inflow wind directions were carried out. The numerical results were compared with the wind tunnel test and field measurement data for land and sea fetches. The results show that the numerical results are in good agreement with the wind tunnel data and the field measurement data which can verify the accuracy and reliability of the numerical simulation. The near ground wind field over complex terrain is complex and affected obviously by the terrain, and the wind field characteristics should be fully understood by numerical simulation when carrying out engineering application on it.

Failure Mode of Orthotropic Two-way Composite Slab under Concentrated Load

Yulin Zhan,Wenfeng Huang,Yu Qiao,Zhouyuan Xu,Renda Zhao 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.12

Ordinary reinforced concrete two-way slabs generally suffer from punching failure under concentrated loads, which is a brittle failure and unfavorable to the structures. The composite slabs with steel sheets and PBL (perfobond rib) shear connectors have been applied for reducing the damage to bridge decks from vehicles. Although it is widely used on bridges, the failure mode of the orthotropic two-way composite slabs has rarely been studied when subject to concentrated loads. Accordingly, static loading tests with concentrated forward central load was carried out on 4 two-way composite slabs, in which the effects of the thickness of steel bottom sheets and concrete plates and spacing of PBL shear connectors on mechanical properties were investigated. The test results show that about 12% of the ultimate bearing capacity decreases when the perfobond ribs are spaced farther apart from 180 mm to 240 mm or the thickness of steel bottom sheets is reduced from 10 mm to 8 mm. And the bearing capacity drops by 38.2% when the thickness of concrete plates decreases by 30 mm. The steel-concrete composite slabs exhibit clear bidirectional force characteristics during the loading process, with the main forced direction being along the perfobond ribs, which is related to the stiffness ratio of the two directions. The two-way composite slabs have high bearing capacity and ductility, with obvious signs before failure. The specimens continue to bear the load after local punching failure of concrete near the loading point, which shows the features of both bending and punching failure. Based on the test results, a bending punching failure mode is proposed, which provides a new approach for the calculation of ultimate bearing capacity. An analytical calculation method for ultimate bearing capacity of orthotropic two-way composite slabs based on the failure mode above is derived with yield line theory and plastic theory, which is in excellent agreement with the tested results.

Influence of thermophilic microorganism on non-volatile metabolites during high-temperature pile-fermentation of Chinese dark tea based on metabolomic analysis

Wen Zhu,Wenfeng Wang,Wencan Xu,Shuang Wu,Wenjun Chen,Youyi Huang,Shengpeng Wang 한국식품과학회 2022 Food Science and Biotechnology Vol.31 No.7

Pile-fermentation is a critical procedure for producing Chinese dark tea, during which thermophilic microorganisms would play an irreplaceable role. However, there have been little researches on the influences of thermophilic microorganism pile-fermentation (TMPF) in high-temperature of Chinese dark tea. Thus, we conducted high-performance liquid chromatography and nontargeted metabolomic to analyze the non-volatile metabolites of TMPF. Our results discovered that the amounts of ( −)-epigallocatechin gallate, ( −)-epigallocatechin, ( −)-epicatechin gallate, and ( −)-epicatechin were decreased significantly (p < 0.05) after TMPF. By using nontargeted metabolomic analysis, a total of 1733 ion features were detected. KEGG pathway enrichment analysis showed that TMPF had a significant impact on caffeine metabolism. Also, theophylline, 3-methylxanthine, and 1,3,7-trimethyluric acid were increased significantly after TMPF, which suggested that demethylation and oxidation reaction might be the main pathways of caffeine metabolism. This study provides a better understanding of the mechanism of TMPF during high-temperature for Chinese dark tea and lays a foundation for further research.

UV-Light Photoelectrochemical Sensor Based on the Copper Tetraamino-Phthalocyanine-modified ITO Electrode for the Detection of Nifedipine in Drugs and Human Serum

Jinyun Peng,Wenfeng Zhuge,Yingying Huang,Cuizhong Zhang,Wei Huang 대한화학회 2019 Bulletin of the Korean Chemical Society Vol.40 No.3

In this study, a new photoelectrochemical (PEC) sensor based on the copper tetraamino-phthalocyanine-modified ITO electrode (CuTAPc/ITO) was designed for the determination of nifedipine. The prepared CuTAPc materials were characterized using UV?Visible spectrophotometry (UVS), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). Then, the CuTAPc solution was coated on the ITO electrode surface to fabricate a simple PEC sensing platform. Then, the photoelectrochemical behavior of nifedipine at the CuTAPc/ITO electrode was investigated by chronoamperometry under ultraviolet light irradiation. The obtained results indicated that the modified electrode showed a higher response signal than the blank electrode. The photocurrent of CuTAPc/ITO increased with the increasing concentration of nifedipine. The peak photocurrents were linearly dependent on the nifedipine concentration in the range of 0.25?18.0 ?mol/L, thereby providing the detection limit of 0.15 ?mol/L (S/N = 3). Due to the good responses for the determination of nifedipine, this sensor can be used as an alternative analysis tool for the detection of nifedipine in various real samples with high sensitivity, low detection limit, and wide linearity range.

Event-triggered Stabilization of Linear Time-delay Systems by Static Output Feedback Control

Xiaoli Wang,Peng Xiang,Wenfeng Hu,Tingwen Huang 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.11

In this paper, we study the stabilization problem for a class of linear systems with a time-varying state delay. An event-triggered static output feedback controller is proposed, such that the sampling frequency and the update time of the controller are both lowered. First, we present a novel event-triggering mechanism depending not only on the output but also on an exponential term, with which less sampling is required and Zeno behavior can be excluded at the same time. Some sufficient conditions are then obtained, under which an exponential convergence can be achieved by means of the comparison principle approach. It is further shown that the parameters design can be easily given if the case reduces to the state feedback control. Moreover, two examples are presented to show the effectiveness of the results.

Refinement of Kinect Sensor’s Depth Maps Based on GMM and CS Theory

Qian Zhang,ShaoMin Li,Wenfeng Guo,Pei Wang,Jifeng Huang 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.5

As the Microsoft’s Kinect sensor can generate a real-time dense depth map with relatively commercial available, it is widely used in depth map capturing. However, there are some artifacts like holes, instability of the raw input data, which seriously affect the application. To solve this problem, in this paper, we propose a novel depth map refinement method based on by GMM and CS theory which enable the kinect sensor generate a dense depth map, the background large holes are filled without blurring, and the edges of the objects are sharpened, median filter is used to remove noise. Experiments on captured indoor data demonstrate the effectiveness of the method especially in the edge area and occlusion area that our method can obtain better results.

A Light-weighted Data Collection Method for DNS Simulation on the Cyber Range

( Shuang Li ),( Shasha Du ),( Wenfeng Huang ),( Siyu Liang ),( Jinxi Deng ),( Le Wang ),( Huiwu Huang ),( Xinhai Liao ),( Shen Su ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.8

The method of DNS data collection is one of the most important parts of DNS simulation. DNS data contains a lot of information. When it comes to analyzing the DNS security issues by simulation on the cyber range with customized features, we only need some of them, such as IP address, domain name information, etc. Therefore, the data we need are supposed to be light-weighted and easy to manipulate. Many researchers have designed different schemes to obtain their datasets, such as LDplayer and Thales system. However, existing solutions consume excessive computational resources, which are not necessary for DNS security simulation. In this paper, we propose a light-weighted active data collection method to prepare the datasets for DNS simulation on cyber range. We evaluate the performance of the method and prove that it can collect DNS data in a short time and store the collected data at a lower storage cost. In addition, we give two examples to illustrate how our method can be used in a variety of applications.

Recent Development of Laboratory-made Solid-phase Microextraction Fibers on the Application of Food Safety Analysis

Jingbin Zeng,Jinmei Chen,Wenfeng Chen,Xiaoli Huang,Liangbi Chen,Xi Chen 한국식품과학회 2009 Food Science and Biotechnology Vol.18 No.3

Solid-phase microextraction (SPME) has gained widespread acceptance in sample pretreatment due to its solventfree and easy-to-operate properties. SPME fibers are considered as a key part of SPME technique, since it primarily determines the extraction performance of the method including sensitivity, selectivity, and reproducibility. Generally speaking, target analyte with different chemical property requires fiber coating that has the best affinity towards it. Due to the lack of varieties of commercial fibers available currently, considerable efforts have been recently made to develop tailor-made fibers to fulfill increasing demands of different analysis. This paper concisely classify some SPME fiber preparation approaches such as solgel technology, physical deposition, molecularly imprinted technique, and their respective application in food safety analysis.