Two-dimensional ocean current Lagrangian coherent structure analytical algorithm

A technology of structural analysis and ocean currents, applied in the field of flow field topology, can solve the problems of lack of strict proof of validity and achieve the effect of clear position

Active Publication Date: 2016-09-28
OCEAN UNIV OF CHINA
View PDF3 Cites 7 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The first type of method is intuitive and simple, and is also used

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Two-dimensional ocean current Lagrangian coherent structure analytical algorithm

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0013] The invention evenly distributes dense grid points in the flow field, and calculates the Cauchy-Green right strain tensor of the movement for a period of time. Based on the local extrema of the tensor's eigenvalues ​​and the eigenvector field, the LCS is integrated (such as figure 1 shown). Include the following steps:

[0014] 1. Calculate the Cauchy-Green right strain tensor of each grid point;

[0015] Firstly, a uniform and dense main grid point is generated in the flow field. In order to improve the calculation accuracy, an additional point is generated at the top, bottom, left, and right sides of each grid point. The spacing between the additional points and the grid points should be much smaller than the spacing between the grid points. All additional points move with the flow field for a period of time. The velocity field is interpolated in the three-dimensional space of longitude, latitude and time, considering the accuracy and speed comprehensively, adopti...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

Abstract

The invention relates to a two-dimensional ocean current Lagrangian coherent structure analytical algorithm. The algorithm is based on a Cauchy-Green right strain tensor, wherein the tensor is obtained in a way that a gradient obtained after particles move for a period of time in a flow field is calculated. Particle movement uses a Runge-Kutta 4 order integration method, and cubic interpolation is adopted for the flow field. In order to improve calculation accuracy, four neighbor points are added on each grid point to calculate the gradient by using a finite difference. The Cauchy-Green right strain tensor is provided with two real eigenvalues, wherein the local maximum value of the large eigenvalue and the local minimum value of the small eigenvalue are seed points of an LCS (Lagrangian Coherent Structure), and the Runge-Kutta 4 order integration is carried out in a non-corresponding characteristic vector field forwards and backwards to obtain a Lagrangian coherent structure. During integration, the direction discontinuity of a character vector is considered. The direction is always kept consistent with the direction of a previous point, and inversion is carried out if the direction differs more than 90 degrees. After one LCS is generated, the LCS seed points in a certain width range of the LCS are set to be ineffective, and an interval between the LCSs is controlled. The Lagrangian coherent structure is an important flow field topological structure, can be effectively applied to the range of ocean current, season-year changes and main flow and branch flow analysis.

Description

technical field [0001] The invention belongs to the field of flow field topology, and in particular relates to a two-dimensional ocean current Lagrangian quasi-order structure analysis algorithm. Background technique [0002] There are two concepts of stable manifold and unstable manifold (stable and unstable manifold) in the time-varying stable flow field. These two manifolds pass through a fixed point with a velocity of 0 in the flow field, and act as a boundary in the flow field: when particles move in the flow field, they will tend to the stable manifold and stay away from the unstable manifold, so that the flow can be The field is divided into different regions. In the unstable flow field, the corresponding concept is Lagrangian coherent structures (LCS), which are divided into attracting LCS and repelling LCS. [0003] The research on S has been developed in the last 20 years. As the dividing line of the unstable field for a certain length of time, the flow through t...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
IPC IPC(8): G06F17/10
CPCG06F17/10
Inventor 田丰林陈戈何珏
Owner OCEAN UNIV OF CHINA
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap