Large Motion Visualization and Estimation for Fluid-Structure Simulations

2015 ◽  
Author(s):  
Tzu-Sheng Shane Hsu ◽  
Timothy Fitzgerald ◽  
Vincent Phuc Nguyen ◽  
Balakumar Balachandran
Keyword(s):  
Objective Function ◽  
High Speed ◽  
Flexible Structures ◽  
Three Dimensional ◽  
Optimization Procedure ◽  
Fluid Structure Interactions ◽  
Displacement Fields ◽  
Fluid Structure ◽  
Computational Implementation

Studies of fluid-structure interactions associated with flexible structures such as flapping wings require the capture and quantification of large motions of bodies that may be opaque. As a case study, motion capture of a free flying insect is considered by using three synchronized high-speed cameras. A solid finite element (FE) representation is used as a reference body and successive snapshots in time of the displacement fields are reconstructed via an optimization procedure. One of the original aspects of this work is the formulation of an objective function and the use of shadow matching and strain-energy regularization. With this objective function, the authors penalize the shape differences between silhouettes of the captured images and the FE representation of the deformed body. A similar method with a three-dimensional voxel cloud (VC) reconstruction is also illustrated. Challenges faced in implementing the VC method are discussed and the current computational implementation will also be covered.

scholarly journals Cross-Flow Tidal Turbines with Highly Flexible Blades—Experimental Flow Field Investigations at Strong Fluid–Structure Interactions

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 797
Author(s):  
Stefan Hoerner ◽  
Iring Kösters ◽  
Laure Vignal ◽  
Olivier Cleynen ◽  
Shokoofeh Abbaszadeh ◽  
...  
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Cross Flow ◽  
Speed Ratio ◽  
Fluid Structure Interactions ◽  
Dimensional Parameter ◽  
Fluid Structure ◽  
Passive Flow Control ◽  
Tidal Turbines ◽  
Tidal Turbine

Oscillating hydrofoils were installed in a water tunnel as a surrogate model for a hydrokinetic cross-flow tidal turbine, enabling the study of the effect of flexible blades on the performance of those devices with high ecological potential. The study focuses on a single tip-speed ratio (equal to 2), the key non-dimensional parameter describing the operating point, and solidity (equal to 1.5), quantifying the robustness of the turbine shape. Both parameters are standard values for cross-flow tidal turbines. Those lead to highly dynamic characteristics in the flow field dominated by dynamic stall. The flow field is investigated at the blade level using high-speed particle image velocimetry measurements. Strong fluid–structure interactions lead to significant structural deformations and highly modified flow fields. The flexibility of the blades is shown to significantly reduce the duration of the periodic stall regime; this observation is achieved through systematic comparison of the flow field, with a quantitative evaluation of the degree of chaotic changes in the wake. In this manner, the study provides insights into the mechanisms of the passive flow control achieved through blade flexibility in cross-flow turbines.

scholarly journals A coupled lattice Boltzmann and Cosserat rod model method for three-dimensional two-way fluid–structure interactions

AIP Advances ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 075020
Author(s):  
Suguru Ando ◽  
Mitsuru Nishikawa ◽  
Masayuki Kaneda ◽  
Kazuhiko Suga
Keyword(s):  
Lattice Boltzmann ◽  
Three Dimensional ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Model Method ◽  
Cosserat Rod ◽  
Rod Model

scholarly journals High-Speed X-ray Stereo Digital Image Correlation for Fluid-Structure Interactions in a Shock Tube

2020 ◽  
Author(s):  
Jeremy James ◽  
Elizabeth M. Jones ◽  
Enrico C. Quintana ◽  
Kyle P. Lynch ◽  
Benjamin R. Halls ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Shock Tube ◽  
Digital Image ◽  
High Speed ◽  
Image Correlation ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
X Ray ◽  
Stereo Digital Image Correlation

On the Mechanics of Phonation and Fluid-Structure Interactions in a Three Dimensional Vocal Fold Model

2007 ◽  
Author(s):  
Somesh Khandelwal ◽  
Thomas Siegmund ◽  
Steve H. Frankel
Keyword(s):  
Vibration Amplitude ◽  
Vocal Fold ◽  
Flow Model ◽  
Three Dimensional ◽  
The Self ◽  
Elastic Response ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Laminar Flow Model

It is hypothesized that the characteristics of vocal fold self oscillation is dependent on the nonlinearity of the solid structure i.e. the tissue. Studies of fluid structure interaction are conducted for three dimensional larynx models. Simulations were performed using the codes FLUENT and ABAQUS coupled by the code MpCCI. For the air an unsteady, laminar flow model was considered. Visco-hyperelasticity was used to characterize the solid domain representing the tissue structure. The computational model is used to conduct a parametric study on the self-oscillation response of the model with focus on the influence of the non-linearity in the hyperelastic response. Individual computations were compared by documenting the variation of the total energy of the structure. It is demonstrated that dissipation in the flow as well as the non-linearity in the elastic response all interact to stabilize or destabilize the vibration amplitude.

scholarly journals Investigation of Fluid-Structure Interaction Induced Bending for Elastic Flaps in a Cross Flow

2020 ◽  
Vol 10 (18) ◽  
pp. 6177 ◽  
Author(s):  
Tayyaba Bano ◽  
Franziska Hegner ◽  
Martin Heinrich ◽  
Ruediger Schwarze
Keyword(s):  
Present Model ◽  
Fluid Structure Interaction ◽  
Flexible Structures ◽  
Three Dimensional ◽  
Cross Flow ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Numerical Investigations ◽  
Transient Simulations ◽  
Ansys Workbench

With the recent increase in the design of light and flexible structures, numerical investigations of fluid and structure together play a significant role in most engineering applications. Therefore, the current study presents an examination of fluid-structure interaction involving flexible structures. The problem is numerically solved by a commercial software ANSYS-Workbench. Two-way coupled three-dimensional transient simulations are carried out for the flexible flaps of different thicknesses in glycerin for a laminar flow and Reynolds number ranging from 3 < Re < 12. The bending line of the flaps is compared with experimental data for different alignments of the flaps relative to the fluid flow. The study reports the computation of the maximum tip-deflection and deformation of flaps fixed at the bottom and mounted normal to the flow. Additionally, drag coefficients for flexible flaps are computed and flow regimes in the wake of the flaps are presented. As well, the study gives an understanding on how the fluid response changes as the structure deforms and the model is appropriate to predict the behavior of thick and comparatively thinner flaps. The results are sufficiently encouraging to consider the present model for analyzing turbulent flow processes against flexible objects.

A Numerical Investigation of the Influence of the Blade–Vortex Interaction on the Dynamic Stall Onset

2021 ◽  
Author(s):  
Camille Castells ◽  
François Richez ◽  
Michel Costes
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Dynamic Stall ◽  
Test Case ◽  
Vortex Interaction ◽  
Fluid Structure ◽  
Speed Test ◽  
Vortex Model ◽  
Flow Parameters ◽  
Blade Vortex Interaction

Recently, fluid–structure coupling simulations of helicopter rotors in high-thrust forward flight suggested that dynamic stall might be triggered by the blade–vortex interaction. However, no clear evidence of a correlation between dynamic stall and blade–vortex interaction has yet been given. We propose in this paper a simplified two-dimensional numerical model that can be used to indicate the role that the blade–vortex interaction plays in dynamic stall onset for different flight conditions. In this model, the rotor blade element is considered in pitching oscillation motion with a nonuniform translation, and a simplified vortex model can be introduced or not in the simulation to highlight the effect of blade–vortex interaction. All flow parameters of this simplified model are deduced from data provided by previous three-dimensional high-fidelity fluid–structure simulations. The method is used for validation and analysis of three flight conditions. The results show that, for the two cases with moderate advance ratio, the dynamic stall event is only triggered when a blade–vortex interaction occurs in the stall region. For the high-speed test case, the dynamic stall event seems to be only triggered by the very high angle of attack due to the motion of the blade.

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