A unifying model for fluid flow and elastic solid deformation: A novel approach for fluid–structure interaction

3D printed hair-like micro-structures have been previously demonstrated in a novel micro-fluidic flow sensor aimed at sensing air flows down to rates of a few milliliters per second. However, there is a lack of in-depth understanding of the structural response of these ‘micro-hairs' under a fluid flow field. This paper demonstrates the use of lattice Boltzmann methods (LBM) to understand this structural response towards a better optimization of the micro-hair flow sensors designed to suit the end applications' needs. The LBM approach was chosen as an efficient alternative to simulate Navier–Stokes equations for modeling fluid flow around complex geometries primarily for improved accuracy and simplicity with lesser computational costs. As the spatial dimensions of the sensor's flow channel are much larger in comparison to the actual micro-hairs (the sensing element), a multidimensional approach of combining two-dimensional (D2Q9) and three-dimensional (D3Q19) lattice configurations were implemented for improved computational speeds and efficiency. The drag force on the micro-hairs was estimated using the momentum-exchange method in the D3Q19 configuration and this drag force is transferred to the structural analysis model which determines the micro-hair deformation using Euler–Bernoulli beam theory. The entirety of the LBM Fluid–Structure Interaction (FSI) model was implemented within MATLAB and the obtained results are compared against the numerical model implemented on a commercially available software package.

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Fluid-Structure Interaction Approach for Numerical Investigation of a Flexible Hydrofoil Deformations in Turbulent Fluid Flow

Volume 4: Fluid-Structure Interaction ◽

10.1115/pvp2018-84637 ◽

2018 ◽

Author(s):

M. Benaouicha ◽

S. Guillou ◽

A. Santa Cruz ◽

H. Trigui

Keyword(s):

Fluid Flow ◽

Numerical Model ◽

Stokes Equations ◽

Fluid Structure Interaction ◽

Time Step ◽

Fluid Structure ◽

Turbulent Fluid Flow ◽

Turbulent Fluid ◽

Structure Interaction ◽

Ale Formulation

The study deals with a 3D Fluid-Structure Interaction (FSI) numerical model of a rectangular cantilevered flexible hydrofoil subjected to a turbulent fluid flow regime. The structural response and dynamic deformations are studied by analyzing the oscillations frequencies and amplitudes, under a hydrodynamics loads. The obtained numerical results are confronted with experimental ones, for validation. The numerical model is performed in the same geometric, physical and material conditions as the experimental set-up carried out in a hydrodynamic tunnel. A polyacetal (POM) flexible hydrofoil NACA0015 with an angle of attack of 8° is considered to be immersed in a fluid flow at a Reynold number of 3 × 105. The structure is initially at rest and then moved by the action of the fluid flow. The numerical model is based on a strong coupling procedure for solving the Fluid-Structure Interaction problem. The Arbitrary Lagrangian-Eulerian (ALE) formulation of the Navier-Stokes equations is used and an anisotropic diffusion equation is solved to compute the fluid mesh velocity and position at each time step. The finite volume method is used for the numerical resolution of the fluid dynamics equations. The structure deformations are described by the linear elasticity equation which is solved by the finite elements method. The Fluid-Structure coupled problem is solved by using the partitioned FSI implicit algorithm. A good agreement between numerical and experimental results for the hydrodynamics coefficients and hydrofoil deformations, maximum deflection and frequencies is obtained. The added mass and damping are analyzed and then the FSI effect on the dynamic deformations of the structure is highlighted.

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A reduced mesh movement method based on pseudo elastic solid for fluid–structure interaction

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406217700177 ◽

2017 ◽

Vol 232 (6) ◽

pp. 973-986

Author(s):

Jize Zhong ◽

Zili Xu

Keyword(s):

Computing Time ◽

Fluid Structure Interaction ◽

Elastic Solid ◽

Continuity Condition ◽

Fluid Structure ◽

Structure Interaction ◽

Wing Flutter ◽

Mesh Movement ◽

Nodal Displacements ◽

Low Order

A reduced mesh movement method based on pseudo elastic solid is developed and applied in fluid–structure interaction problems in this paper. The flow mesh domain is assumed to be a pseudo elastic solid. The vibration equation for the structure and the pseudo elastic solid together is derived by applying the displacement continuity condition on the fluid–structure interface. Considering that the actual fluid–structure coupled vibration for structures often appears to be associated with low-order modes, the nodal displacements for the structure and the flow mesh can be computed using the modal superposition of a few low-order modes. Coupled fluid–structure computations are performed for flutter problems of a beam and wing 445.6 using the present method. The calculated results are consistent with the data reported in other references. The computing time is reduced by 65.5% for the beam flutter and 54.8% for the wing flutter compared with the pre-existing elastic solid method.

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