Abstract
It will be helpful to further understand the mechanism of wind effects on the corner cutting cylinders by
investigating the wind flows under different inflow wind angles of attack. In this study, a large eddy simulation method was
adopted to study the effect of corner cutting on the aerodynamic performance of a square cylinder in smooth flow. The
numerical method and parameter settings were first verified by comparing the simulation results of the square cylinder without
corner cutting with previous experimental and numerical results. Then, the effect of corner cutting on the aerodynamic
performance of the square cylinder was analysed by comparing the wind pressure distribution and the aerodynamic forces. The
corner cutting modification of the square cylinder will significantly supress the development of the aerodynamic forces.
Compared with the standard square cylinder, the Strouhal number decreases about 1.48 times under wind angle with 0°.
Comparison to the standard square cylinder showed that similar three flow patterns can also be observed around the corner
cutting square cylinder, albeit with different ranges of the incidence angle for each flow pattern. When corner cutting is adopted,
the flow separation position moves downstream, and the separated shear layer approaches the cylinder and is more prone to
reattachment on the lateral surface, resulting in a narrow wake flow and reducing the strength of vortex shedding. This is the
main origin of the decrease in the aerodynamic coefficient of the corner cutting square cylinder and the flow field mechanism
that leads to an increase in the Strouhal number.
Key Words
aerodynamic performance; corner cutting; flow mechanism; large eddy simulation; square cylinder
Address
Deqian Zheng:School of Civil Engineering, Henan University of Technology, Zhengzhou, 450001, China
Wei Yan: School of Civil Engineering, Henan University of Technology, Zhengzhou, 450001, China
Wenyong Ma: School of Civil Engineering, Shijiazhuang Tiedao University, Shijiazhuang, 050043, China
Lang Li: School of Civil Engineering, Henan University of Technology, Zhengzhou, 450001, China
Junhao Wu: School of Civil Engineering, Henan University of Technology, Zhengzhou, 450001, China
Shuaiyong Liu: School of Civil Engineering, Shantou University, Shantou, 515063, China
Abstract
The primary goal of this research is to explore the influence of structural responses brought about by alterations in
aerodynamic characteristics resulting from the incorporation of leading-edge protuberance (LEP) blades in vertical-axis wind
turbines (VAWTs). A scaled-down straight-blade VAWT was utilized and subjected to operational wind speeds at a fixed pitch
angle and various blade configurations to carry out this investigation. The study specifically aimed to investigate the unsteady
structural excitation caused by the decay of vortices due to different aerodynamic loads and their effects on the VAWT structure.
The results demonstrated that counter-rotating vortices in the LEP profile enhanced the aerodynamics of the blades at higher
angles of attack. Understanding the structural characteristics resulting from aerodynamic changes is essential for developing
VAWTs. The current research analyzes the effects of LEP on the structural excitation of a VAWT by examining the acceleration
and displacement data obtained from a static-structure VAWT for various solidity ratios and LEP profiles. The results indicated
that the VAWT with LEP blades resulted in decreased acceleration and displacement amplitudes for a low solidity ratio, which
increased with an increase in the solidity ratio. Significant aerodynamic and structural damping were observed in the VAWT
with LEP blades. These results were in close agreement with the time and frequency domains of the measured displacement and
acceleration of the structure. The average bi-directional vibration damping of approximately 35% was observed by substituting
the straight blade with the LEP blades for the operation of VAWT.
Key Words
aerodynamic damping; dynamic stall; experimental study; leading edge protuberance; passive flow control;
solidity ratio; VAWT
Address
Karthik Vel Elangovan: Turbulence & Flow Control Laboratory, SASTRA Deemed to Be University, Thanjavur, Tamil Nadu-613041, India
Nadaraja Pillai S: Turbulence & Flow Control Laboratory, SASTRA Deemed to Be University, Thanjavur, Tamil Nadu-613041, India
Abstract
A long-span suspension bridge is an engineering background investigating how a suspension bridge and a train
respond to wind loads in coupling vibration. The three-component coefficient of the bridge is calculated using Fluent software,
and the random wind field is simulated using the wavelet analysis method. An analysis model of wind-train-bridge coupling
vibration is developed based on structural dynamics principles considering track irregularities and hunting movements, by
combining a self-written calculation program with general finite element software, the system's dynamic responses under wind
and train loads are studied, and the train's safety and comfort are evaluated. The findings indicate that the numerical simulation
results of the three-component force coefficient of the main girder of a long-span steel truss suspension bridge are reasonable in
this paper, and the random wind field obtained by the wavelet analysis method accords with the randomness of natural wind.
The long-span suspension bridge's natural frequencies are low and highly susceptible to wind loads. The train's running safety
and comfort decrease with the increase in wind velocity, and the system's dynamic responses increase with the wind velocity.
The influence of wind-induced vibration in bridges is significantly higher than the train's effect. As the train speed increases, the
dynamic responses of the system also increase, resulting in a decrease in the train's running safety and comfort, the train's shock
actions on the bridge do not have a significant impact. When the wind velocity exceeds 20 m/s, the train's running safety at 300
km/h cannot be ensured, meeting the relevant provisions of "Technical Management Regulations for Railway". It can provide a
reference for the operation decision of long-span bridges with similar geometric characteristics in crosswind environments.
Key Words
comfort evaluation; dynamic response; long-span suspension bridge; random wind field; running safety; threecomponent force coefficient; wind–train–bridge sys
Address
Xing Wan: School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China
Shaoqin Wang: School of Science, Beijing University of Civil Engineering and Architecture, Beijing 100032, China
Chuanqiang Xu: School of Civil and Transportation Engineering, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
Hong Qiao: School of Civil and Transportation Engineering, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
Xun Zhang: School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China
Abstract
Radar echo data, which include surface meteorological information, are frequently required for various types of
weather predictions. However, the spatial resolution of meteorological radar data is typically on the order of kilometers.
Additionally, various environmental factors can interfere with radar data acquisition, leading to instability and frequent data
gaps. To solve this problem, the physics informed neural network (PINN) is utilized to reconstruct the radar measured
convective storm in Nanchang, so as to supplement the missing radar echo data. Navier-Stokes equation is encoded in PINN as
the prior physical knowledge. The reconstruction errors are also statistically analyzed. What' s more, the evolutionary mesoscale
features of the convective storm are briefly described. The field survey is conducted to evaluate the wind disaster losses in
Nanchang. Results show that the severe convective weather in Nanchang on March 30, 2024, was a typical squall line event.
The reconstruction method based on PINN effectively compensates for missing radar wind data. The reconstruction errors
approximately follow a Weibull distribution, with most significant errors occurring near the boundaries of the missing data
regions, which has a limited impact on analyzing mesoscale features of convective storm.
Key Words
convective storm; physics-informed neural network; radar echo data; wind disaster survey; wind field
reconstruction
Address
Zidong Xu: Key Laboratory of C&PC Structures of Ministry of Education, Southeast University, Nanjing 211189, China
Hao Wang: Key Laboratory of C&PC Structures of Ministry of Education, Southeast University, Nanjing 211189, China
Kaiyong Zhao: Key Laboratory of C&PC Structures of Ministry of Education, Southeast University, Nanjing 211189, China
Shulin Zhi: Jiangxi Meteorological Observatory, Nanchang 330096, China
Ruliang Wang: Jiangxi Meteorological Observatory, Nanchang 330096, China
Rui Zhou: Key Laboratory of C&PC Structures of Ministry of Education, Southeast University, Nanjing 211189, China
Yuxuan Lin: Key Laboratory of C&PC Structures of Ministry of Education, Southeast University, Nanjing 211189, China
Han Zhang: Key Laboratory of C&PC Structures of Ministry of Education, Southeast University, Nanjing 211189, China
Abstract
In this paper, a novel multi-objective optimization framework is proposed for the global dimensions of the lowspeed wind tunnel supported by the Belt and Road Joint Laboratory (BRJL-LWT). Three indexes are considered in the process:
the flow quality index, the total pressure loss index and the test section volume index. The flow quality is taken as a constraint on
the aerodynamic requirements, while pursuing a larger test section space and lower total pressure loss. A multi-objective
optimization algorithm is adopted as the solver for the optimization process at four initial flow velocities. The results show that
the flow quality of the optimized large test section fully meets the target requirements for structure fluid testing. The total
pressure loss index is inversely proportional to the test section volume index for all initial flow velocities. Finally, the optimal
BRJL-LWT dimensions are determined and the optimal BRJL-LWT model is developed. The fluid analyses are performed to
assess the flow uniformity and turbulence intensity of the fluid within the test section. This optimization framework not only
enables the designed wind tunnel to produce the required flow field conditions, but also makes efficient use of the test section
space and reduces the facility's operational energy consumption, which significantly extends the applicability of the wind tunnel
design.
Key Words
dimensions design; flow quality; large test section; multi-objective optimization; wind tunnel
Address
Wen-Peng Xu: 1)China-Pakistan Belt and Road Joint Laboratory on Smart Disaster Prevention of Major Infrastructures,
Southeast University, Nanjing 210096, China
2) School of Civil Engineering, Southeast University, Nanjing 210096, China
Luca Martinelli: Department of Civil and Environmental Engineering, Politecnico di Milano, Milan 20133, Italy
Zhao-Dong Xu: 1)China-Pakistan Belt and Road Joint Laboratory on Smart Disaster Prevention of Major Infrastructures,
Southeast University, Nanjing 210096, China
2) School of Civil Engineering, Southeast University, Nanjing 210096, China
Jun Dai: 1) China-Pakistan Belt and Road Joint Laboratory on Smart Disaster Prevention of Major Infrastructures,
Southeast University, Nanjing 210096, China 2) School of Resources and Civil Engineering, Northeastern University, Shenyang 110819, China
