Fluid–Structure Interaction of a Flexible Structure in a Turbulent Flow using LES

Author(s):  
M. Breuer ◽  
G. De Nayer ◽  
M. Münsch
2018 ◽  
Author(s):  
H. R. Díaz-Ojeda ◽  
L. M. González ◽  
F. J. Huera-Huarte

The aim of this paper is to evaluate how much affects the presence of gravity and free-surface to a flexible structure in a classical fluid structure interaction (FSI) problem typically found in off-shore problems and other oceanic applications. The base problem selected is the Turek benchmark case where a deformable plate is attached to the wake of a circular cylinder. To focus on the differences of considering free surface, a simple geometry has been selected and two different situations have been studied: the first one is the classical Turek benchmark, the second is a similar geometry but adding gravity and free surface. The free surface problem was studied placing the structure at different depths and monitoring the deformation and forces on the structure.


Author(s):  
Hariyo P. S. Pratomo

Abstract In this work, the application of a shear stress transport based-RANS/LES turbulence modelling approach on a fluid-structure interaction (FSI) benchmark is considered after a transient computation of turbulent flow over the configuration on an LES quality mesh is to be performed. Within the unsteady decoupled simulation the scale resolving method successfully produces complex unsteady eddy sizes behind the reference test case. At a subcritical Reynolds number, a numerical Strouhal number of 0.184 which is close to a reference value of 0.18 is demonstrated by the RANS/LES turbulence model. In this scenario, a rubber added on the back part of a fixed circular cylinder is treated as a rigid thin plate during the pure flow simulation. On the LES grid resolution, the shielding function resided in the hybrid limiter of the scale resolving formulation is found to be strong to safeguard the activation of the RANS mode in the near wall region where the demarcation line between the RANS and LES modes uniquely resembles the geometry. Moreover, in the FSI simulation resolved turbulence scales interacting with moving and deforming rubber immersed in the subcritical Reynolds number-turbulent flow are successfully captured by the hybrid modelling technique coupled with a structural solver under the coupling procedure of an implicit partitioned approach. Similar with earlier studies with different scale-resolving proposals on the same FSI case, a periodic oscillating motion of the rubber that is produced from a phase-averaging method is also demonstrated in this present investigation. Nevertheless, a non-physical deformation of the rubber in the spanwise direction occurs. The new FSI result is evaluated with existing results from earlier works as a pivotal basis for further researches, such as implementations of new mesh stiffness model and filter width.


2019 ◽  
Vol 7 (5) ◽  
pp. 839-848 ◽  
Author(s):  
Mingyang Wang ◽  
Eldad J. Avital ◽  
Xin Bai ◽  
Chunning Ji ◽  
Dong Xu ◽  
...  

AbstractA fluid–structure interaction (FSI) methodology is presented for simulating elastic bodies embedded and/or encapsulating viscous incompressible fluid. The fluid solver is based on finite volume and the large eddy simulation approach to account for turbulent flow. The structural dynamic solver is based on the combined finite element method–discrete element method (FEM-DEM). The two solvers are tied up using an immersed boundary method (IBM) iterative algorithm to improve information transfer between the two solvers. The FSI solver is applied to submerged vegetation stems and blades of small-scale horizontal axis kinetic turbines. Both bodies are slender and of cylinder-like shape. While the stem mostly experiences a dominant drag force, the blade experiences a dominant lift force. Following verification cases of a single-stem deformation and a spinning Magnus blade in laminar flows, vegetation flexible stems and flexible rotor blades are analysed, while they are embedded in turbulent flow. It is shown that the single stem’s flexibility has higher effect on the flow as compared to the rigid stem than when in a dense vegetation patch. Making a marine kinetic turbine rotor flexible has the potential of significantly reducing the power production due to undesired twisting and bending of the blades. These studies point to the importance of FSI in flow problems where there is a noticeable deflection of a cylinder-shaped body and the capability of coupling FEM-DEM with flow solver through IBM.


Sign in / Sign up

Export Citation Format

Share Document