Sonar Barrier Component Surface Patterning for Drag Reduction
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Solution Overview
Problem
Sonar systems face noise interference due to movement through water, leading to increased hydrodynamic drag and reduced sensitivity, particularly in towed arrays where drag is proportional to the power of 4, and bio-fouling issues in tropical environments.
Innovation Solution
A barrier component with a repeating pattern of surface features, such as pillars and ridges, formed in rows on the outer surface, with heights and spacings less than 10µm, applied during manufacturing processes like extrusion or moulding, to reduce hydrodynamic drag and prevent bio-fouling, using materials like polyurethane or polyvinyl chloride.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the sonar system moves through water, then it can detect objects and navigate, but hydrodynamic drag increases and flow noise is generated
Solution Approach 1:
The outer surface is segmented into multiple rows of surface features (pillars or ridges) spaced at specific intervals. This segmentation disrupts the continuous flow of water, reducing hydrodynamic drag and flow noise generation while allowing the sonar system to move through water effectively.
Solution Approach 2:
The surface features are applied locally to the outer surface of the barrier component rather than the entire structure. The specific geometry, height, and spacing of pillars or ridges are optimized for the local water-flow interaction, reducing drag and noise while maintaining structural integrity.
2Ease of manufacture
If the barrier component surface is smooth, then manufacturing is easier, but bio-fouling occurs in tropical environments
Solution Approach 1:
The continuous surface is segmented into rows of pillars or ridges with specific spacing. This segmentation creates a surface structure that is difficult for bio-fouling organisms to attach to, while still being manufacturable using standard extrusion or moulding processes.
Solution Approach 2:
The surface geometry parameters (height less than 10μm, spacing less than 5μm) are specifically optimized to prevent bio-fouling. These parameter changes transform the surface from a smooth, bio-friendly configuration to a bio-resistant structure that can be manufactured with standard processes.
3Object-affected harmful factors
If surface features are made larger, then bio-fouling prevention is more effective, but hydrodynamic drag increases
Solution Approach 1:
The surface feature dimensions are precisely controlled with height less than 10μm and spacing less than 5μm. These specific parameter values are optimized to prevent bio-fouling while minimizing the disruption to water flow, thereby reducing hydrodynamic drag compared to larger surface features.
Solution Approach 2:
The surface features are applied partially to the outer surface rather than the entire structure. This partial application provides sufficient bio-fouling prevention while minimizing the total surface area that could potentially increase hydrodynamic drag.
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 patterned surface reduces hydrodynamic drag, lowers flow noise, enhances sonar system performance, and extends mission duration by decreasing fuel or energy consumption, while also preventing bio-fouling and maintaining surface cleanliness.
Implementation Method 1
at least a part of the outer surface of the barrier component comprises a repeating pattern, wherein the repeating pattern comprises surface features formed in rows
Implementation Method 2
The patterned surface reduces hydrodynamic drag, lowers flow noise
Implementation Method 3
preventing bio-fouling and maintaining surface cleanliness
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
The present disclosure relates to a barrier component (10) for a sonar system and a method of manufacturing a barrier component for a sonar system. At least a part of the outer surface (18) of the barrier component (10) comprises a repeating pattern, wherein the repeating pattern comprises surface features (16) formed in rows, wherein the surface features have a height of less than 10µm.