Rollable Large-Aperture Planar Array for Stable Ocean Towing
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Solution Overview
Problem
Existing large aperture sensor arrays for ocean acoustic sensing are difficult to deploy and control due to their size and shape, exacerbated by sea-state motion, wave slap, and wind, and require a stable, collapsible design for easy storage and retrieval.
Innovation Solution
A vertically stacked array of hydrophone tubes with neutrally buoyant center and buoyant sections connected by hinges, actuated by radial ducted fins to roll up around the center tube, allowing easy deployment and retrieval, and a closure mechanism to stabilize the array during towing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large aperture planar or volumetric sensor array is used for ocean acoustic sensing, then acoustic sensing capability is improved, but deployment and control difficulty increases due to size and shape
Solution Approach 1:
The array is divided into multiple modular sections that can be independently handled and assembled. Each section contains a manageable number of sensors and can be deployed separately, then connected to form the complete large aperture array, making deployment feasible despite the overall large size
Solution Approach 2:
The array is configured as a planar structure rather than a volumetric one, reducing the third dimension and simplifying deployment. The planar geometry allows the array to be deployed in a single plane, reducing complexity compared to three-dimensional volumetric arrays while maintaining large aperture capabilities
2Measurement precision
If a large aperture planar array is used for acoustic sensing, then acoustic sensing capability is improved, but stability deteriorates due to sea-state motion, wave slap, and wind
Solution Approach 1:
Buoyancy elements are strategically positioned to counteract the effects of wave slap and sea-state motion. The buoyant sections provide upward force to compensate for downward impacts from waves, while ballast elements provide downward force to maintain vertical orientation and resist wind-induced instability
Solution Approach 2:
The array incorporates flexible connections and adjustable positioning mechanisms that allow the structure to adapt dynamically to changing sea conditions. The array can adjust its configuration in response to wave patterns and wind forces, maintaining stability through controlled movement rather than rigid resistance
3Ease of operation
If a collapsible array design is used for easy storage and retrieval, then ease of operation is improved, but device complexity increases due to folding and rolling mechanisms
Solution Approach 1:
The array sections are designed to nest within each other when collapsed, with smaller sections fitting inside larger ones. This nested configuration minimizes storage volume and simplifies retrieval, as the entire array can be compacted into a small package that fits on board the support vessel
Solution Approach 2:
The array employs flexible connections and collapsible tubular structures that can bend and fold without damaging the sensors. These flexible elements allow the rigid sensor components to be housed within flexible protective sheaths that can be easily rolled and stored while maintaining sensor integrity
4Ease of manufacture
If a collapsible array design is used for easy storage, then storage ease is improved, but manufacturing complexity increases due to hinge and actuator assembly
Solution Approach 1:
The array incorporates self-actuating mechanisms that use the natural buoyancy forces and water current to drive the folding and rolling actions. The buoyant sections automatically extend the array during deployment without requiring external actuators, and the same buoyancy forces assist in the collapse process, reducing the need for complex mechanical actuation systems
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 array provides stable acoustic data collection with reduced drag and ease of storage, enabling efficient deployment and retrieval, while maintaining acoustic integrity and minimizing hydrodynamic noise.
Implementation Method 1
A vertically stacked array of hydrophone tubes with neutrally buoyant center and buoyant sections
Implementation Method 2
The actuator assembly includes a plurality of adjustable fins. The fins are connected to an actuator that can change the angle of attack of the fins and, when subjected to environmental fluid flow, induce a torque on the center tube
Data Source
AI summary
A planar sensor array includes a center tube, a first group of tubes, and a second group of tubes. One or more of the first group of tubes is positively buoyant, and at least one of the second group of tubes is negatively buoyant. Adjacent tubes are joined together by hinges. Acoustic sensors are positioned within the tubes. First and second half-shells are connected to the most distal tube of each group. The first half-shell is positively buoyant, and the second half-shell is negatively buoyant. An actuator attached to said center tube, and fins are attached to the actuator. The actuator is adjustable to change the fins angle of attack. Environmental fluid flow over the fins induces a torque on the actuator and center tube and causes these components to rotate. Rotation of the center tube causes the first and second groups of tubes to wrap around the center tube.