Flexible Bubble Curtain for Underwater Noise Damping
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Solution Overview
Problem
Existing bubble curtain systems for damping underwater noise during offshore wind farm construction are inefficient, requiring multiple setups for effective noise reduction, which is costly and prone to clogging due to sediment intrusion when air supply is interrupted.
Innovation Solution
A bubble curtain system comprising a flexible pressure line with a high number of small air bubbles, a membrane with angled slots to prevent sediment entry, and a design that ensures uniform air discharge along the length, achieving higher noise reduction through scattering and reflection rather than resonant absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If large air bubbles are used in the bubble curtain to achieve resonant absorption at the impact noise frequency, then the damping effect is improved, but the noise reduction is insufficient for single mast ramming operations
Solution Approach 1:
The invention changes the key parameter of bubble diameter from large (prior art) to small (1-5 mm). This parameter change fundamentally alters the noise reduction mechanism from resonant absorption to scattering and reflection, achieving superior damping效果 with a single bubble curtain instead of multiple curtains
Solution Approach 2:
The invention utilizes the vibration and movement of numerous small bubbles to scatter and reflect sound waves. The collective mechanical response of many small bubbles creates effective noise barriers through scattering and reflection rather than resonant absorption
2Use of energy by moving object
If the air supply is interrupted to stop compressed air consumption, then energy saving is achieved, but sediment penetrates into the pressure line causing clogging
Solution Approach 1:
The membrane performs preliminary protective action by preventing sediment from entering the pressure line before the air supply is interrupted. This preliminary protection ensures that when air supply stops and pressure drops, sediment cannot penetrate into the system, maintaining reliability for subsequent restarts
Solution Approach 2:
The membrane acts as an intermediary barrier between the external environment (containing sediment) and the internal pressure line. It selectively allows air to pass through while blocking sediment particles, protecting the system during air supply interruptions
3Device complexity
If a single bubble curtain generating device is used for cost reduction, then device complexity is reduced, but the damping effect is insufficient for high-impulse ramming operations
Solution Approach 1:
By changing the bubble size parameter to small (1-5 mm) bubbles and adjusting the air flow distribution, a single bubble curtain achieves the noise damping effectiveness that previously required multiple larger bubble curtains. This parameter change enables one device to replace multiple devices
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves significantly higher noise reduction with lower compressed air consumption, increased reliability by preventing sediment clogging, and can be used on uneven seabeds with improved manufacturing simplicity.
Implementation Method 1
The pressure line is surrounded by a membrane through which small air bubbles are released. The pressure line is supplied with compressed air
Implementation Method 2
Another advantage is that the large number of small bubbles lead to more scattering of the sound waves of the piling noise and to a stronger reflection of the piling noise
Implementation Method 3
Another advantage is that the large number of small bubbles lead to more scattering of the sound waves of the piling noise and to a stronger reflection of the piling noise
Implementation Method 4
The ambient pressure closes the slot securely
Data Source
Figure 1
Figure 2
AI summary
The device has a membrane that is used to discharge the compressed air in a form of bubbles (20) through multiple pores into surrounding water. A pressure line (12) has a wall that is surrounded by the membrane in the vicinity of multiple apertures, such that the compressed air is emitted through the apertures, and then through the pores into the water. The aperture cross-sections and the pore sizes are selected, such that the pressure of the compressed air over the membrane is decreased at most 30% and 20% respectively. An independent claim is included for a method of attenuating the underwater sound.