Analysis of Fluid-Structure Interaction by Means of Dynamic Unstructured Meshes

Abstract

This paper presents a computational analysis on forced vibration and fluid-structure interaction in compressible flow regimes. A so-called staggered approach is pursued where the fluid and structure are integrated in time by distinct solvers. Their interaction is then taken into account by a coupling algorithm. The unsteady fluid motion is simulated by means of an explicit time-accurate solver. For the fluid-structure interaction problems which are considered here the effects due to the viscosity can be neglected. The fluid is hence modeled by the Euler equations for compressible inviscid flow. Unstructured grids are used to discretise the fluid domain. These grids are particularly suited to simulate unsteady flows over complex geometries by their capacity of being dynamically refined and unrefined. Dynamic mesh adaptation is used to enhance the computational precision with minimal CPU and memory constraints. Fluid-structure interaction involves moving boundaries. Therefore the Arbitrary Lagrange Euler method (ALE-method) is adopted to solve the Euler equations on a moving domain. The deformation of the mesh is controlled by means of a spring analogy in conjunction with a boundary correction to circumvent the principle of Saint Venant. To take advantage of the differences between fluid and structure time scales, the fluid calculation is subcycled within the structural time step. Numerical results are presented for large rotation, pitching oscillation and aeroelastic motion of the NACA0012 airfoil. The boundary deformation is validated by comparing the numerical solution for a flat plate under supersonic flow with the analytical solution.

A finite‐volume particle method for conservation laws on moving domains

“…Therefore, they are also called geometrical coefficients. Only from formula (17), one would say that they play an important role in the scheme. Indeed, they have a significant influence on the properties of the method.…”

“…Finally one should note that (17) contains two unknowns at the time level n +1, namely u by differentiating Equation (8) with respect to t, namelyV…”

Spectral Element andhpMethods

“…Specifically, the idea of variable diffusivity as in Lohner and Yang (1996) was incorporated into the spring model while maintaining the computational efficiency of the methods used in Batina (1990), Rausch, Batina and Yang (1994), and Blom and Leyland (1998). The combination of these two methodologies provides a computationally efficient way of minimizing edge crossover in situations in which Laplacian smoothing fails.…”

“…Other researchers have attempted to calculate the mesh deformation using coordinate smoothing methods (Batina, 1990;Rausch, Batina and Yang, 1994;Blom and Leyland, 1998). Mesh positions are obtained using methods based on a graph theory analogy to the spring problem.…”

Lift maximization with uncertainties for the optimization of high‐lift devices

“…Therefore, boundary displacement does not spread far into the mesh. A boundary-improvement technique was suggested to handle this localization of deformation [18]. The stiffness of springs adjacent to the boundary was increased so that surface displacement could be spread further into the mesh.…”