Incident Wave Extraction for Diffraction-Affected Offshore Structures
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Solution Overview
Problem
Existing methods fail to accurately extract near-field incident waves acting on fixed offshore engineering structures like mono-pile turbines and bridge piers due to diffraction effects, leading to superposition of incident and diffraction wave components, which complicates the estimation of wave loads and hinders safe operation.
Innovation Solution
A method involving dimensionless parameter calculation, wave theory classification, continuous wavelet transformation, and diffraction theory separation to decompose measured waves into incident and diffraction components, using Meyer's wave classification chart and Morelet's wavelet function to extract near-field incident waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wave buoys are arranged far away from the structures to avoid collision damage, then the safety of the structures is improved, but the measurement precision of near-field incident waves deteriorates
Solution Approach 1:
The patent introduces wave radars as intermediary devices mounted on the structures to measure wave parameters. These radars act as mediators between the structures and the wave field, enabling near-field wave measurement without requiring physical wave buoys in the water, thus avoiding collision risks while achieving precise measurement.
Solution Approach 2:
The patent replaces the mechanical wave buoy system with an electromagnetic wave radar system. Instead of using physical buoys that float on water and are prone to collision, the invention uses wave radars that emit and receive electromagnetic waves to measure wave parameters, substituting a mechanical measurement system with an electromagnetic one.
2Measurement precision
If wave radars are fixed on the structures to measure near-field waves, then the measurement precision of near-field waves is improved, but the reliability of wave information deteriorates due to diffraction effects
Solution Approach 1:
The patent segments the measured wave signal into distinct components: incident wave components and diffraction wave components. By applying signal processing techniques, the total measured signal is decomposed into these separate elements, allowing the incident wave information to be extracted independently from the diffraction effects.
Solution Approach 2:
The patent extracts the incident wave components from the composite measured signal by removing the diffraction wave components. This extraction process isolates the pure incident wave information that is needed for accurate wave load calculation, separating it from the contaminating diffraction effects.
3Ease of operation
If existing separation methods for incident and reflected waves are applied to fixed offshore structures, then the ease of operation is improved, but the measurement precision deteriorates because these methods are designed for linear harbor structures not cylindrical offshore structures
Solution Approach 1:
The patent modifies the wave separation approach by incorporating the specific geometric parameters of cylindrical offshore structures (radius, height, position) into the diffraction theory model. This parameter adaptation transforms the generic separation method into a structure-specific method that accounts for the cylindrical geometry, thereby improving measurement precision.
Solution Approach 2:
The patent applies local quality by tailoring the wave separation method to the specific characteristics of cylindrical offshore structures. Instead of using a universal method designed for linear harbor structures, the invention customizes the diffraction theory application to match the local geometric properties of the cylindrical structures, ensuring accurate incident wave extraction for this specific structure type.
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
Accurately separates incident waves from disturbance waves, improving calculation efficiency and accuracy, ensuring reliable estimation of wave loads for safe operation of offshore structures.
Implementation Method 1
directly measure near-field wave time courses of the structures through wave radar fixed on the offshore engineering structures
Implementation Method 2
due to large scales of the fixed offshore engineering structures such as mono-pile wind turbines and bridge piers, there is a diffraction effect on wave propagation
Data Source
AI summary
Disclosed is a method for extracting near-field incident waves of a fixed offshore engineering structure. The method includes the steps: calculating a dimensionless wave height parameter and a dimensionless water depth parameter based on measured wave information, and selecting applicable wave theories; obtaining analytic signals of measured waves at one or two wave measuring points according to classification of the wave theories; calculating components occupied by incident waves in disturbance waves based on a first-order diffraction theory and a second-order diffraction theory respectively according to the classification; separating the wavelet signal analytic signals according to a proportion of the components of the incident waves for wavelet inverse transformation, to obtain the near-field incident waves of the fixed offshore engineering structure. The present invention can effectively take into account both computational efficiency and accuracy.