Shaopeng Li

• PhD
• Professor at Chongqing University

Focused on optimizing the vortex-induced vibration (VIV) of bridge towers, this study explores the aerodynamic characteristics of tandem rectangular cylinders with varying corner recess sizes through three-dimensional large eddy simulation. The effects of corner recess on aerodynamic forces, mean and fluctuating pressure distributions, flow structu...

The transient effect of downburst-like flow on the unsteadiness and non-stationarity of fluctuating lift force acting on a rectangular cylinder is an important aerodynamic issue. Using the multiple-fan active control wind tunnel, the transient aerodynamic characteristics of fluctuating lift force under downburst-like flow are studied. It is observe...

Wind power is a pivotal clean energy source worldwide. The structural safety and dynamic response analysis of wind turbines is significantly impacted by the availability and precision of wind speed data at their location. However, the sparse distribution of meteorological stations often makes it difficult to obtain high-resolution spatial wind spee...

This paper mainly studies the impact of turbulence scale on unsteady cross-wind loading (CWL) on high-rise buildings (HRBs) in wind tunnel tests. Wind tunnel tests were conducted utilizing a 2:1 rectangular rigid segment pressure measurement model to analyze the influence of the scale ratio Lw/B (where Lw represents the turbulence scale in cross-wi...

Turbulence spectral analysis is a critical aspect of wind tunnel experiments. In this study, a modification of the Mann uniform shear model (M94), based on the Rapid Distortion theory, is proposed to adapt M94 for wind tunnel conditions and model the complete second-order turbulence structure. First, the one-point spectra measured at heights rangin...

This study investigates the coupled responses between the alongwind and acrosswind directions of a variable cross-section bridge tower model through wind tunnel experiments, Uniform and two turbulent flows with four different wind directions are designed to study their influences. The results show a significant coupling effect between the alongwind...

The aerodynamic shape of the bluff body plays a significant role in determining the unsteady drag force resulting from the three-dimensional (3D) distortion of approaching free-stream turbulence. This paper conducted pressure measurements of bluff bodies with four different cross sections (square, rectangular, circular, elliptic, with different asp...

The paper focuses on studying the unsteadiness, three-dimensionality, and distortion of free-stream turbulence approaching the stagnation point of an elongated bluff body. This aerodynamic problem is complicated because of the combination of blocking, distortion, and three-dimensional (3D) effects. Using the spectral tensor concept, a closed-form s...

The flow structure and reattaching characteristic of two tandem rectangular cylinders with aspect ratio being 5:1 have been investigated through wind tunnel experiments and three-dimensional large eddy simulation (LES) methods. The gap width G between the two cylinders varies from 2 times of D to 20 times of D, where D represents the depth of the t...

Thunderstorm downbursts are transient in nature and have been responsible for a variety of structural damages in recent years. Currently, the researchers have done several works on the characteristics of downburst wind speed. Nonetheless, rare attention has been placed on the structural aerodynamics characteristics subjected to downburst winds. Bas...

The assessment of buffeting response of long span bridges relies significantly on the aerodynamic admittance and spanwise coherence functions of buffeting forces acting on bridge decks. This study presents a novel approach to derive admittance and coherence functions of buffeting lift on bridge decks, utilizing wind tunnel measurement of forces on...

Wind velocity is usually assumed to obey a stationary stochastic process in wind engineering, and this may cause significant bias in describing extremely severe strong wind such as typhoons and thunderstorms. To take into account the non-stationary characteristics of extreme wind, a novel evolutionary power spectral density (EPSD) model is proposed...

Traditional pressure measurements fail to determine the buffeting force on bridge decks with complex configurations, such as truss or box girders with two slabs. The high-frequency force balance (HFFB) provides an efficient way to solve this aerodynamic issue. This work aims to clarify the spatial distribution characteristics of gust loading acting...

This study presents a novel methodology, the enhanced higher-order spectral representation method (HOSRM), designed for the effective simulation of multivariate non-Gaussian stochastic processes. This approach first extends the spectral representation method by introducing the Einstein tensor representation of cross-spectra and cross-trispectra, th...

The present work aims to experimentally investigate the influence of wind directionality on the three-dimensionality of buffeting force on a streamlined bridge deck, considering the pylon interference effect (PIE). The pylon has an obvious impact on the downstream flow structure under the skew wind, influencing the aerodynamic loads acting on the b...

In this work, a generalized fourth-order spectral representation method (SRM) is proposed for symmetrically non-linear non-Gaussian random processes. An analytical formula is derived to simulate the generalized fourth-order non-Gaussian random process. Another significant feature of this method is the efficient combination of the Fast Fourier Trans...

The distortion of turbulence approaching a bluff body plays a dominant role in determining the unsteadiness of the fluctuating surface pressures. A three-dimensional (3D) spectral approach is proposed to decouple the effects of the distorted turbulence into the blocking effect, distortion effect, and 3D effect. Wind tunnel tests are conducted to in...

Featured Application A normalized across-wind fluctuating wind load spectrum model is proposed, taking into account the effects of incoming turbulence, the side ratio, vortex shedding, and separation reattachment flow-induced spectral bandwidth changes and high-frequency fluctuations. Abstract The present work is devoted to the role of boundary la...

In this study, a new higher-order spectral representation method (HOSRM) is derived to simulate fourth-order (kurtosis-order) non-Gaussian random processes. Applying the HOSRM allows fourth-order non-Gaussian random process (symmetric non-Gaussian) sample functions to be generated accurately. As the number of terms in the cosine function used in th...

This paper presents an experimental investigation of buffeting lift forces on a central-slotted box girder in turbulentflow, and aims to identify the corresponding generalized aerodynamic admittance (generalized-AAF) andtwo-dimensional aerodynamic admittance (2D-AAF). The generalized-AAF is obtained using the onewavenumber spectra of lift and wind...

This study aims to investigate the influence of turbulent three-dimensional (3D) and distortion effects on the unsteady lateral buffeting force of trains on a streamlined deck and propose a closed form equation for the 3D aerodynamic admittance function (AAF). Six fluctuating wind fields were simulated to analyze the influences of different turbule...

In order to study the scale effect of turbulence on the buffeting force on a bluff body, pressure measurements on a rigid sectional model were conducted in the wind tunnel. The emphasis was placed on investigating the effect of integral length scale of turbulence on the spanwise correlation and spatial distribution of lateral buffeting force on a r...

The experimental errors of the buffeting force caused by the scale effect become more significant when the reproduced turbulence scale is not very large in comparison with the characteristic dimension of the test model. From a fluid mechanics perspective, the scale effect can be divided into the three-dimensional (3D) effect in the spanwise directi...

To investigate the influence of the wind attack on a bridge deck’s flutter performance, the concept of “pressure flutter derivatives” was introduced as a part of the “distributed aerodynamic characteristics” method, which can be used to visualize the dominant fluctuations of the pressure field. The distributions of the aerodynamic damping and stiff...

In conventional buffeting analyses for long-span bridges, the aerodynamic admittance functions (AAF) with respect to the longitudinal (u-) and vertical (w-) turbulence components are usually assumed to be equivalent. This assumption could cause unpredictable errors due to complicated turbulence-structure interactions. This study proposes an experim...

A reasonable extreme probability model to estimate the transient loads is essential for structural wind resistance design. The transient aerodynamic characteristics of a 5:1 rectangular cylinder under thunderstorm-like wind are experimentally studied based on the multiple-fan active wind tunnel technique. In this paper, the non-Gaussian characteris...

Downbursts exhibit pronounced transient effects and nonstationary characteristics. Herein, a pressure measurement test of a rigid segment model under a downburst-like wind is conducted on a 5:1 rectangular cylinder using a multi-fan active control wind tunnel. Based on the experimental results, downburst-like wind field and wind load characteristic...

The present work aims to study the effects of turbulence intensity on the three-dimensional spatial distribution of unsteady gust loading on a 5:1 rectangular cylinder. Three types of grids are adopted to produce uniform turbulent flows with different turbulence intensities and constant integral scales. The experimental results show that the turbul...

Random load identification (including load localization and reconstruction) plays a great significance in structural optimization design and safety evaluation. However, conventional methods perform the identification on the premise of an entire knowledge on excitation locations, which is hard to be predetermined in practice. Meanwhile, these method...

Synchronized surface pressure measurements and forced motion techniques are performed in a wind tunnel to investigate the aerodynamic characteristics of an oscillatory rectangular cylinder with a 5:1 benchmark section. The effects of the vertical and torsional vibration amplitude and the Reynolds number (Re) on the streamwise surface pressure are s...

Scale effect has a non-negligible influence on the buffeting response of a slender linear structure. Among them, the effect of the ratio of the turbulence integral scale to the structure width is widely recognised. However, past research neglected the role of the aspect ratio, and the experiments did not accurately simulate the turbulence character...

The traditional method for calculating the buffeting response of long-span bridges follows the strip assumption, and is carried out by identifying aerodynamic parameters through sectional model force or pressure measurement wind tunnel tests. However, there has been no report on predicting the buffeting response based on the sectional model vibrati...

The shape of a bluff body section is of high importance to its aerostatic performance. Obtaining the aerostatic performance of a specific shape based on wind tunnel tests and CFD simulations takes a lot of time, which affects evaluation efficiency. This paper proposes a novel fully convolutional neural network model that enables rapid prediction fr...

The aerodynamic loadings of a 5:1 rectangular cylinder in one-dimensional sinusoidal flows are experimentally tested in a multiple-fan active control wind tunnel. A series of single-frequency streamwise sinusoidal flows, which are fully coherent in the spanwise direction, are generated by changing the frequency and amplitude. Spectral analysis indi...

Active winglets, with a manually controlled attitude angle, can take advantage of the self-excited force to suppress the flutter tendency of a bridge girder. Previous studies mostly focused on the effectiveness and robustness under long-term closed-loop control. However, the deck-winglet system’s short-term response, due to the memory effect of the...

The aerodynamic behavior of a 5:1 rectangular cylinder at angles of attack (AoA) up to 15° is investigated based on Three-dimensional Large-Eddy Simulations (3D LES) and instantaneous pressure measurements. The numerical results indicate that the separated flow is highly sensitive to AoA and involves two patterns: (i) the flow reattaches to the bot...

Three-dimensional Large-Eddy Simulations (3D LES) are performed to study the separated and reattaching flow over a 5:1 rectangular cylinder in streamwise sinusoidal flow. The ratio of inflow frequency to natural vortex-shedding frequency is varied from 0 to 6 at five amplitudes up to 60% of the time-mean velocity. The effect on the two-dimensional...

In this study, three-dimensional Large-Eddy Simulations (3D LES) are conducted to investigate the near-wake characteristics of a 5:1 rectangular cylinder in oscillating flow. The oscillating flow is generated by introducing a sinusoidal velocity perturbation to the smooth flow at a low Reynolds number. It is observed that the dynamics of the vortic...

The vortex-induced vibration behavior and mechanism of an asymmetrical composite beam cable-stayed bridge is investigated by means of aerodynamic sectional tests and computational fluid dynamics methods. Tests are performed for the bridge deck under five wind attack angles (0°, ±2.5°, and ±5°) and two wind directions (0° and 180°) during the comple...

3D LES approaches were applied to study the unsteady behavior of a rectangular 5:1 (width-height ratio) cylinder due to sinusoidal oscillating flow. The pressure distributions on conditions of uniform flow were compared between experimental and numerical results, and the numerical ones agreed well with experimental ones. The effects of oscillating...

In this paper, the generalized one-wavenumber aerodynamic admittance (3D one-wavenumber AAF), two-wavenumber aerodynamic admittance (3D two-wavenumber AAF) and two-dimensional aerodynamic admittance with the second (spanwise) wavenumber k2=0 (2D AAF) of streamlined bridge decks in free stream turbulence are investigated based on Ribner's three-dime...

The aim of the present work is to propose a generalized approach to derive the closed-form solution for three-dimensional aerodynamic admittance (3D AAF), which can describe the spatial distribution of the lift force on streamlined bridge decks in turbulent flow. Using Rinber’s three-dimensional theory, the solutions presented herein are only depen...

The goal of the present work is to derive the closed-form expressions of coherence and admittances to describe the spatial distribution of lift on rectangular cylinders in turbulent flow, which can be used to investigate the three-dimensional effects of turbulence. The coherence of the three-dimensional aerodynamic admittance (3D AAF), which takes...

The pressure fluctuations acting on a stationary rectangular prism with cross configuration (2:1/1:2) are investigated by wind tunnel testing. The synchronous surface pressures on the rigid model were measured in simulated atmospheric boundary layer flow and the unsteady forces were calculated by numerical integral of surface pressures. The effects...

The unsteady lift of a stationary airfoil encountering a sinusoidal streamwise gust is experimentally investigated under attached flow conditions. The airfoil has an NACA 0015 profile with a chord length c = 0.5 m. The Reynolds number of the main flow is in the range of 198 000 ⩽ Re ⩽ 331 000. The reduced frequency of the perturbation ω ranges from...

In order to study the spatial distribution of buffeting drag on bluff bodies and the mechanism of flow-structure interaction, the span-wise correlation and the energy distribution of buffeting drag on stationary rectangular cylinder with side ratio B/D=2 were investigated by synchronically surface pressure measurement. The results show that the buf...

In order to reduce the error of buffeting forces calculation induced by the traditional coherence model expressed in simple exponential form, a double-exponential coherence model with definite physical significance was proposed based on three-dimensional buffeting analysis of thin aerofoil. This model could be extended to bluff bodies with complica...

In order to refine the studies of static wind load on the deck of cable-stayed bridge under skew wind, a full bridge ‘aero-stiff’ model technique was used to identify the aerostatic loads on each deck segment, in smooth oncoming flow, with various yaw angles. the experimental results indicated that the shelter effect of the pylon may not be ignored...

The effect of skewed flow on the spanwise correlation of buffeting forces on rectangular cylinders is investigated by synchronically surface pressure measurement. It indicates that the spanwise correlation of buffeting forces is almost independent of the wind directions even when the yaw angle is up to 30º.

In conventional buffeting theory, it is assumed that the aerostatic coefficients along a bridge deck follow the strip assumption. The validity of this assumption is suspect for a cable-stayed bridge in the construction stages, due to the effect of significant aerodynamic interference from the pylon. This situation may be aggravated in skew winds. T...

In order to study the characteristics of unsteady aerodynamic forces (buffeting forces) on a bluff body, a rectangular cylinder is taken as an example. A pressure measurement technique was applied to study the span-wise buffeting force on the cylinder under turbulent flow with different integral length scales. The deficiencies of traditional 2-dime...

The three-dimensional effects of turbulence cannot be neglected when the spanwise wavelength of the incident turbulence is not effectively infinite with respect to the chord, which may invalidate the strip assumption. Based on three-dimensional theory, a general approach, expressed in terms of a two-dimensional Fourier transform of the correlation...

In order to modify the uncertainty of joint acceptance function in buffeting response estimation induced by the traditional coherence model of wind fluctuation, represented in simple exponential form, an improved coherence model for theoretical method was proposed through the introduction of some extra parameters. The proposed coherence model succe...

Results of previous wind tunnel testing have shown that the span-wise correlation of the buffeting force on bridge deck is greater than that of the turbulent components. Due to the limitation of wind tunnel size and model scale, above-mentioned results were usually obtained for smaller separation along the span and the turbulent flow was generated...