Submarine Hydrodynamic Coefficient Determination via Self-Service Maneuvers
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Solution Overview
Problem
Current methods for determining hydrodynamic coefficients in submarines are imprecise, especially for real submarines, leading to inaccurate predictions of boat behavior and the need for complex and approximate large-scale tests.
Innovation Solution
A method involving free-floating submarines with a front and rear hydroplane, where the vessel undergoes various speed and trim attitude conditions to measure hydrodynamic coefficients directly, allowing for precise determination of these coefficients without external forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If theoretical calculation or model tests are used to determine hydrodynamic coefficients, then the measurement process is simplified, but the precision and accuracy of the coefficients deteriorate
Solution Approach 1:
The submarine determines its own hydrodynamic coefficients by performing maneuvers and measuring forces/moments during operation. The system uses the submarine's own propulsion and control surfaces to generate the necessary motion, and its own sensors to measure the resulting forces, eliminating the need for external towing facilities or model test tanks.
Solution Approach 2:
The method involves changing operational parameters (speed, depth, rudder angles, elevator angles) to create different flow conditions. By measuring forces and moments across multiple parameter combinations, the system can separate and determine individual hydrodynamic coefficients through mathematical analysis.
2Measurement precision
If full-scale tests are used to verify hydrodynamic coefficients, then the accuracy for real submarines improves, but the complexity and cost of the testing process increases
Solution Approach 1:
The submarine performs self-testing by executing predefined maneuver sequences and using its own sensor suite to collect data. The processing unit automatically analyzes the collected force and moment data to determine the hydrodynamic coefficients, eliminating the need for external test facilities, towing equipment, or complex data processing infrastructure.
Solution Approach 2:
The method uses dynamic maneuvers (changes in speed, depth, and attitude) rather than static measurements. By performing acceleration phases, constant-speed cruising, and maneuvering with control surfaces, the system captures hydrodynamic forces under various dynamic conditions, providing comprehensive coefficient determination.
3Ease of operation
If approximate values are used for hydrodynamic coefficients, then the complexity of the determination process is reduced, but the precision of boat behavior prediction deteriorates
Solution Approach 1:
The system uses feedback from actual operational measurements to determine the hydrodynamic coefficients. By comparing measured forces and moments during controlled maneuvers with theoretical models, the system iteratively refines the coefficient values to match actual submarine behavior, providing precise predictions for maneuvering and control.
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
This method enables exact and individual measurement of hydrodynamic coefficients, improving the precision of boat behavior prediction and eliminating the need for imprecise model tests, allowing for more controlled and accurate submarine maneuvers.
Implementation Method 1
When a submarine is traveling at a steady speed, the normal force acting on the boat is zero. When the boat is stationary, the trim moments acting on it are zero.
Implementation Method 2
W the weight of the submarine including flooded free spaces
Data Source
Figure 1
AI summary
The present invention relates to a method for determining hydrodynamic coefficients in submarines by travels without acceleration.