Wind-Induced Vibration
Tackling Wind-Induced Vibrations in Tall, Slender Structures
Can a mild breeze topple a structure designed to withstand a hurricane? For tall, slender structures like process columns and steel stacks, the answer could be yes. Under the right wind conditions, these structures begin to vibrate and have little inherent ability to limit the amplitude of response, potentially leading to damage and even failure.
At Equity, we recognize the impact of wind forces on these structures. Our multidisciplinary team provides advanced analysis and customized solutions to reduce wind-induced vibration risks and ensure long-term reliability.
Key Factors in Wind-Induced Vibrations
Wind-induced vibrations can reach dangerous amplitudes in tall, slender process equipment. Effective mitigation requires understanding of several key factors:
- Wind hazard analysis and load calculation
- Dynamic fluid-structure interaction
- Process equipment analysis and design
- Fatigue assessment techniques
What is Vortex Shedding?
Vortex shedding happens when fluid flows around an object, creating alternating low-pressure vortices on its downstream side. The frequency of these vortices depends on the object’s shape, the flow speed, and a factor known as the Strouhal number (S), which is typically around 0.2 for cylindrical objects in wind.
This shedding creates forces that act across the object, and if the frequency of these forces matches the natural frequency of the structure, resonance occurs. Predicting the resulting vibration amplitude is challenging because it is highly sensitive to the structure’s ability to dissipate energy (structural damping), which is difficult to accurately estimate.
While there are various methods to assess vortex shedding resonance, there is no single approach widely accepted by US codes and standards.
Structural Solutions
Our Mechanical & Structural Engineering team is equipped to rapidly solve these problems and preserve structural integrity using the following approach:
- Assessment & Diagnosis: Using PlantManager SAGE, we model the structure under both shutdown and operating conditions, providing insights into the factors contributing to wind-induced vibrations, including vortex shedding and interaction between adjacent structures.
- Inspection & Repair: We develop an inspection plan that targets the areas most susceptible to damage and develop a repair plan if needed to prevent further issues.
- Mitigation Strategy: We assess a variety of mitigation techniques including stiffness, aerodynamic, and damping-based approaches to optimize a solution and effectively eliminate the resonant response.
Why Equity?
Our Mechanical & Structural Engineering team is equipped to diagnose, assess, and resolve complex wind-induced vibration problems quickly and efficiently. Using advanced tools like PlantManager SAGE, we assess both strength and fatigue concerns, providing reliable insights and actionable recommendations.
By implementing our recommendations, clients have reduced wind-induced vibrations, uncovered previously undetected cracks, saved millions in potential repairs, reduced safety hazards, and minimized operational downtime. With our broad industry expertise, Equity Engineering is the trusted partner for reliable and tailored solutions to even the most challenging vibration issues.
