Low Drag Dipping Sonar Cable Dynamics
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Solution Overview
Problem
The deployment of airborne dipping sonars in anti-submarine warfare is limited by the significant drag generated by the cable, which restricts the speed of antenna lowering and raising, and requires a winch capable of handling substantial tensile forces, leading to increased cable dimensions and drag.
Innovation Solution
A dipping sonar system with a motorized winch and a battery-powered antenna that can be independently operated, reducing the need for power transfer through the cable, and featuring deployable arms and rings to minimize drag during operation, with a clamp mechanism to manage cable tension and deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the cable length is increased to reach greater depths, then the detection depth is improved, but the drag force increases significantly
Solution Approach 1:
The cable is designed with variable cross-sectional area along its length, with thicker sections at the top and thinner sections at the bottom. This dynamic variation in cable dimensions allows the cable to withstand higher tensile forces near the surface while reducing drag in deeper water, thus resolving the contradiction between cable length and drag force.
Solution Approach 2:
The cable's physical parameters, specifically its cross-sectional area, are changed along its length to optimize performance. The cable has a non-uniform structure with different diameters at different positions, allowing it to adapt to varying mechanical stresses and hydrodynamic conditions at different depths.
2Strength
If the cable cross-sectional area is increased to withstand higher tensile forces, then the strength is improved, but the drag force increases
Solution Approach 1:
Different sections of the cable have different cross-sectional areas optimized for their specific functions. The upper sections have larger cross-sections to handle the full weight and drag, while lower sections have smaller cross-sections since they only need to support the antenna weight. This local differentiation resolves the contradiction between strength and drag.
Solution Approach 2:
The cable's cross-sectional area varies dynamically along its length, creating a tapered structure that is thick where maximum strength is needed and thin where drag must be minimized. This dynamic parameter variation allows the cable to simultaneously achieve high strength and low drag.
3Speed
If the antenna weight is increased to overcome cable drag during lowering, then the lowering speed is improved, but the raising force requirement increases
Solution Approach 1:
The system uses the antenna's own weight as a counterbalance to the cable drag during lowering operations. By carefully selecting the antenna weight, the system achieves optimal lowering speed without requiring additional driving force, while the winch only needs to provide force to overcome the difference between antenna weight and cable drag.
Data Source
AI summary
A low-drag dipping sonar includes an antenna equipped with acoustic transmitters and receivers. The dipping sonar further comprises a motorized winch comprising a reel, and an actuator configured to rotate the reel and a cable wound on the reel, in that the winch is placed in the antenna, and in that the cable allows the antenna to be hooked to a carrier at its one free end of the cable.