With the increasing complexity and height of modern building structures, wind load has become one of the important factors in structural design. As a special form of wind load, the influence of fluctuating wind on the structure cannot be ignored. This article will discuss how to consider the influence of fluctuating wind on structures in engineering design.
First, the characteristics of pulsating wind.
Pulsating winds are generated by turbulence at various scales in the wind field and are random and non-stationary. Its characteristics mainly include:
1.Time-domain characteristics: The intensity, frequency and direction of the fluctuating wind all change with time, showing strong randomness.
2.Spatial characteristics: There are differences in the characteristics of the wind field in different locations, and the magnitude and direction of wind speed are spatially unevenly distributed.
3.Turbulent characteristics: Turbulent wind contains turbulence of different scales, and its turbulence intensity, scale and spatial correlation have different effects on the structure.
Second, the influence of pulsating wind on the structure.
The influence of fluctuating wind on the structure is mainly manifested in the following aspects:
1.Dynamic response: The dynamic pressure generated by the pulsating wind acts on the structure, causing the structure to vibrate and deform. Loud vibrations can cause fatigue, damage, and even destruction of the structure.
2.Wind-induced vibration: Structural vibrations caused by pulsating wind can be divided into two categories, namely downwind vibration and crosswind vibration. Downwind vibration mainly affects the comfort of the structure, while crosswind vibration can cause fatigue and damage to the structure.
3.Aerodynamic stability: The vortex shedding and flow field disturbance caused by the fluctuating wind may affect the stability of the structure, and in severe cases, it may lead to structural instability.
4.Aeroelasticity and dynamic stability: Aeroelastic and dynamic stability problems caused by pulsating wind can lead to irreversible deformation or damage to the structure.
3. Measures to consider pulsating wind in engineering design.
In order to reduce the influence of fluctuating wind on the structure, the following measures should be taken in the engineering design:
1.Optimize the structural design: according to the meteorological data of the project location, combined with the characteristics and use requirements of the structure, the structural form and layout are reasonably selected to improve the wind resistance of the structure.
2.Establish a refined model: Numerical simulation methods are used to establish a refined model to simulate the characteristics of fluctuating wind and its influence on the structure, so as to provide a basis for structural design.
3.Introduce pneumatic measures: By setting pneumatic measures such as nozzles and deflectors, the influence of vortex shedding and flow field disorder on the structure is reduced. At the same time, vibration damping devices such as dampers can be used to reduce the vibration of the structure.
4.Wind tunnel test: Conduct wind tunnel test on important or complex structures to understand their dynamic characteristics and response under the action of fluctuating wind, so as to provide a basis for structural design.
5.Strengthen monitoring and maintenance: Establish a structural health monitoring system to monitor the vibration and deformation of the structure in real time, and find and deal with potential problems in a timely manner. At the same time, regular maintenance and overhaul are carried out to ensure the normal use of the structure.
IV. Conclusions. In summary, it is important to consider the impact of fluctuating wind on the structure in the engineering design. In order to reduce the influence of fluctuating wind on the structure, it is necessary to have an in-depth understanding of the characteristics of fluctuating wind and its influence mechanism on the structure, and take corresponding measures to design, optimize and maintain the structure. At the same time, the application of numerical simulation and wind tunnel test should be strengthened to provide a more scientific and reliable basis for structural design.