Pulsating Wind Harmonic Superposition Along-Wind Fluctuation Effects on High-Rise and Tall Structures

In the design of high-rise buildings and tall structures, wind load represents a critical consideration, particularly the fluctuating effects of wind. Natural wind is not steady flow but contains substantial random pulsating components that affect the structural dynamic response.

Pulsating wind pressure can typically be simulated using the harmonic superposition method. This approach decomposes random wind fluctuations into multiple harmonic components with different frequencies, phases, and amplitudes, then superimposes these components to approximate actual pulsating wind loads. The method is widely adopted in structural wind engineering due to its computational efficiency and straightforward implementation. From a coding perspective, this involves generating multiple sine waves with randomized phases using functions like numpy.random.uniform() for phase generation and numpy.fft for frequency domain processing, followed by summation using vectorized operations.

For high-rise and tall structures, along-wind fluctuation effects are particularly significant. As structural height increases, wind speed varies along the height (wind profile effect), and pulsating wind pressure induces structural vibrations. These vibrations may lead to structural fatigue, reduced comfort, or even failure. Therefore, structural design requires accurate evaluation of pulsating wind effects and implementation of appropriate wind-resistant measures such as optimizing structural shape, adding damping systems, or adjusting structural stiffness. In computational implementation, this typically involves solving differential equations of motion using numerical integration methods like Newmark-beta or Runge-Kutta algorithms.

The harmonic superposition method can be used not only for deterministic analysis but also combined with random vibration theory to further investigate structural dynamic response characteristics, thereby providing comprehensive assessment of wind load effects on structures. This integration often requires spectral analysis techniques and probability density function calculations to characterize response statistics.