Fluid Solid Boundary Definition in CFD Simulations
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Solution Overview
Problem
Current computational fluid dynamics simulations face inefficiencies in defining the boundary between solid and fluid regions due to slow nearest neighbor search algorithms, especially when the number of grid points and node points increases, leading to prolonged computing times, even with advanced algorithms like ANN and kd-Tree.
Innovation Solution
A method that quickly defines the boundary between a solid object model and a fluid region by using intersecting points of straight lines with the solid object model's surface, determining whether grid points are inside the solid or fluid region, thereby reducing computing time through efficient nearest neighbor searches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nearest neighbor search algorithms (ANN, kd-Tree) are used to define fluid/solid boundaries, then boundary definition capability is achieved, but computing time becomes excessively long when number of grid points and node points increases
Solution Approach 1:
The patent segments the boundary definition process into two independent phases: (1) pre-calculating and storing intersection points of straight lines with the solid object model surface, and (2) using these pre-computed intersections to rapidly determine grid point positions. This segmentation allows the computationally intensive geometric analysis to be performed once during model preparation, enabling fast iterative boundary definitions during simulation.
Solution Approach 2:
The patent performs preliminary action by pre-calculating the intersection points of straight lines with the solid object model surface and storing them in advance. This preliminary computation eliminates the need to perform complex geometric intersection calculations during each iterative boundary definition, significantly reducing computing time in large-scale simulations.
2Adaptability or versatility
If iterative boundary search is performed for moving and deforming solid objects, then adaptability to motion is achieved, but computing time becomes enormous
Solution Approach 1:
The patent performs preliminary action by pre-computing and storing intersection points during model preparation. When the solid object model moves or deforms, the boundary definition can be rapidly updated by simply reassigning grid points based on the pre-computed geometric relationships, rather than performing expensive nearest neighbor searches again, thus maintaining adaptability with minimal computational cost.
Solution Approach 2:
The patent creates a copy of the geometric relationship information through pre-computed intersection points. This copied geometric data structure can be rapidly queried and reused during iterative simulations of moving and deforming objects, avoiding the need to recalculate complex geometric intersections at each iteration.
Data Source
AI summary
A method for defining a fluid/solid boundary for computational fluid dynamics simulations making use of a coordinate system mesh and a solid object model, which includes the steps of defining straight lines on which all of the grid points of the coordinate system mesh are positioned; obtaining intersecting points of the straight lines with the surface of the solid object model; and a step in which, for each of the straight lines having the intersecting points, the grid points on the straight line are searched for the nearest point to each of the intersecting points, and based on the searched-out nearest points, the positioned grid points are determined as to whether the grid point is positioned inside the solid object model or in the fluid region.