Study On Radial Basis Function Interpolation In Data Exchange For Fluid-structure Interaction

As a new type of interpolation method, radial basis function(RBF) has aadvantage of clear mathematical concepts and low requirement of the form of CSD/CFD grid, and it’s beneficial to develop independent procedures to realize thecoupling analysis which make it valuable in theoretical research and practicalengineering applications. For solving the problem that the data exchange can notrealize directly between nodes on the non-matching meshes of the common interfacefor fluid-structure interaction(FSI) analysis, the matrix for data exchange offluid-structure interaction is derived with the RBF interpolation method in this paper,and the data transmission errors on coupling interface in different dimension spacesare analyzed, then the influence of mesh density and different radial basis functionsfor the data exchange is discussed, and apply it to the actual fluid-structure interactionanalysis. The main research contents are as follows:1. The basic theory of fluid-structure interaction and the energy conservationprinciple of data exchange on coupling interface are introduced, and the concept ofradial basis function is expounded, as well as the RBF interpolation and its boundaryconditions. The data exchange matrix for fluid-structure interaction is mainly derived,and using the data exchange program written by Matlab, the data transmission errorfor line contact, two-dimensional and three-dimensional surface are calculated, andthe results show that the RBF interpolation for data exchange of fluid-structureinteraction interface has high accuracy, which can meet needs of the practicalprojects.2. The impact of mesh density for the radial basis function interpolation in FSIdata exchange is analyzed, and the relationship between mesh density and theaccuracy of data transfer, which can provide a reference for the selection of meshdensity in the actual FSI data transmission. The effect of different radial basisfunction for the error of data transfer process is also compared, and the3d surfaceexample is calculated using the appropriate RBF interpolation procedures, the resultsshow different radial basis function have no visible effect on the error of dataexchange. However, taking the volume spline function as the basis function of RBFinterpolation to calculate the coupling matrix, the data transmission error is relativelysmall, and can save a part of the calculation time.3. The data exchange of actual fluid-structure interaction analysis are researched for the unidirectional coupling model of the impact of water on the sheet and themodel of wind turbine blades, as well as the bidirectional coupling model of bendingpipes with the variable pressure flow with the RBF interpolation method, and theresults calculated by the program of RBF interpolation and the one-way/two-wayfluid-structure interaction analysis module of universal ANSYS Workbench areconsistent and have small calculation errors.In short, with the research of the RBF interpolation method of data exchange forfluid-structure interaction and the application of the method for unidirectional andbidirectional coupling problems, the article provide a guide and reference for the dataexchange at the coupling interface for FSI problems.