Wind Tunnel Study of Wind Pressures on a Super-Tall Building

In wind tunnel studies of super-tall buildings, synchronous multi-point pressure measurement on rigid models is a key technique for understanding complex surface pressure distributions and aerodynamic mechanisms. High-precision pressure scanning valve systems capture real-time pressure fluctuations at various points under transient wind fields, providing high spatiotemporal resolution data on instantaneous pressure. This refined methodology offers a solid data foundation for revealing the dynamic response of super-tall buildings in complex wind environments.

1.Refined Synchronous Pressure Measurement and Building Interference Effects

The core advantages of pressure scanning valve technology are its synchronism and high throughput. Unlike traditional sequential single-point measurements, synchronous techniques record the simultaneous wind pressure state across all measurement points at any given instant. This is crucial for analyzing unsteady, separation-dominated wind loads, especially during strong vortex shedding or reattachment. Synchronous pressure data is the only reliable way to reveal the underlying physics in such flows.

Using this high-precision data, research can systematically investigate "building interference effects"—how surrounding buildings at different spacings and heights influence the wind loads on a target super-tall building. These effects manifest as:

Significant Impact on Local Wind Pressure: Upstream interfering buildings alter the incoming wind speed profile, turbulence structure, and attack angle, causing drastic changes in local pressures on the target building. In specific positions, an interferer can amplify vortex-induced suction on the target's sides, distort positive pressure zones on the windward face, or generate extreme suction due to "channelling effects" or "downfall vortices." These local pressure changes directly impact the design of cladding components (e.g., curtain walls, glass, panels).

Alteration of Overall Aerodynamic Forces: Interference effects also modify the overall wind forces (base shear, moment) and torque on the target structure. Integrating surface pressures yields time histories of these overall forces. Comparing statistical characteristics (mean, RMS, peak values) and power spectral densities of these forces with and without interferers, or under different interference configurations, quantifies the impact on the structural load state, identifying whether conditions become more or less severe.

2. Providing Reliable Basis and Improved Methods for Wind Load Design

The ultimate goal of this research is to provide a more scientific and reliable basis for engineering design.

For cladding design, which depends on local peak pressures, the experimentally obtained peak suction and pressure data can directly determine design wind pressures for components, ensuring sufficient safety margins even under the most adverse interference conditions.

For structural design, which focuses on overall forces, significant increases in base moments due to interference must be accounted for to ensure structural strength and serviceability.

However, translating dynamic wind loads into practical Equivalent Static Wind Loads (ESWL) remains challenging. The applicability of methods codified in standards (e.g., Gust Loading Factor methods based on background and resonant response) needs re-evaluation in complex interference scenarios. This study uses synchronous multi-pressure data to assess current ESWL methods from two perspectives:

Safety Assessment: Examining whether current methods can envelope the more adverse dynamic responses found under interference, or if they risk underestimating contributions from higher modes or changes in spatial correlation.

Economic Assessment: Analyzing whether current methods are overly conservative for less critical interference cases, leading to material waste and higher costs.

Based on this, the research proposes improved ESWL methods derived from the real, synchronously measured pressure fields. These methods can more accurately represent the spatial distribution of wind loads and their coupling with structural modes. Potential improvements include: load reconstruction based on Proper Orthogonal Decomposition (POD) of the pressure field, developing more rational dynamic amplification factors accounting for interference, or proposing multi-objective ESWL combination methods for different design targets (e.g., inter-story drift, acceleration). This aims to produce design loads that are both safe and cost-effective.

3. Value of Experimental Data for CFD Model Validation

Beyond direct engineering application, the detailed, high-fidelity instantaneous pressure data from these wind tunnel tests holds significant scientific value—serving as a benchmark for validating and calibrating Computational Fluid Dynamics (CFD) numerical models.

CFD is increasingly used in wind engineering, but its predictive accuracy for complex separated flows and surface pressures heavily depends on the turbulence model, near-wall treatment, computational grid, and boundary conditions. Systematically comparing CFD results—including mean and fluctuating pressure distributions, pressure coefficients, and force spectra—against the synchronous wind tunnel data allows researchers to:

Identify Discrepancies: Pinpoint areas and conditions where CFD predictions show significant errors.

Calibrate Models: Adjust and optimize key CFD parameters (e.g., turbulence model constants) or computational strategies (e.g., meshing) based on the comparisons to improve predictive capability.

Establish Confidence: A CFD model rigorously validated against experimental data gains higher credibility, enabling its reliable use for extended parametric studies and simulating complex scenarios difficult to replicate in wind tunnels.

In summary, synchronous pressure measurement wind tunnel testing, utilizing pressure scanning valves, forms a complete research cycle: from refined measurement and mechanism analysis to engineering application and model validation. It provides critical data for the wind-resistant design of super-tall buildings in complex environments, drives advancements in ESWL methods, and lays a solid foundation for enhancing the accuracy and standardized use of CFD, thereby contributing significantly to both wind engineering science and safe, economical construction.