scholarly journals Image-based tracking technique assessment and application to a fluid–structure interaction experiment

2019 ◽  
Vol 233 (16) ◽  
pp. 5724-5734 ◽  
Author(s):  
DA Mella ◽  
W Brevis ◽  
JE Higham ◽  
V Racic ◽  
L Susmel
Keyword(s):  
Fluid Structure Interaction ◽  
Sampling Frequency ◽  
Image Resolution ◽  
Target Motion ◽  
Image Correlation ◽  
Correct Selection ◽  
Measuring Device ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Interaction Experiment

This work analyses the accuracy and capabilities of two image-based tracking techniques related to digital image correlation and the Lucas–Kanade optical flow method, with the subsequent quantification of body motion in a fluid–structure interaction experiment. A computer-controlled shaker was used as a benchmark case to create a one-dimensional oscillatory target motion. Three target frequencies were recorded. The measurements obtained with a low-cost digital camera were compared to a high-precision motion tracking system. The comparison was performed under changes in image resolution, target motion and sampling frequency. The results show that, with a correct selection of the processing parameters, both tracking techniques were able to track the main motion and frequency of the target even after a reduction of four and five times the sampling frequency and image resolution, respectively. Within this good agreement, the Lucas–Kanade technique shows better accuracy under tested conditions, achieving up to 15.6% of lower tracking error. Nevertheless, the achievement of this higher accuracy is highly dependent on the position of the selected initial target point. These considerations are addressed to satisfactorily track the response of a wall-mounted cylinder subjected to a range of turbulent flows using a single camera as the measuring device.

The Ocean Cleanup System 001 Performance During Towing and Seakeeping Tests

2019 ◽  
Author(s):  
Joost Sterenborg ◽  
Nicola Grasso ◽  
Rogier Schouten ◽  
Arjen Tjallema
Keyword(s):  
Fluid Structure Interaction ◽  
Model Tests ◽  
Operating Conditions ◽  
Image Correlation ◽  
Plastic Pollution ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Wave Basin ◽  
Floating System ◽  
Floating Systems

Abstract One of the aims of The Ocean Cleanup is to develop technologies to extract plastic pollution from the world’s oceans. Several concepts of passive floating systems were considered that are supposed to confine plastics to ease their collection. Such concepts consist of a floating member and a submerged flexible skirt and have in common that their span is generally more than 500 meters. Consequently, fluid-structure interaction plays an important role in the response of such a floating system. To support numerical simulations, MARIN carried out extensive model tests on a 120 meter system section of the final concept, with focus on the fluid-structure interaction (FSI) of the submerged skirt in operating conditions and in towing configuration. The ability to capture plastics was not investigated in these model tests. Novel for wave-basin tests were non-intrusive measurements using underwater Digital Image Correlation (DIC) to obtain the displacements and deformations of the flexible skirt. DIC proved to be a capable measurement technique for this type of structure in combination with a wave basin. Detailed quantitative data on skirt motions and deformations were delivered and the last concept of the cleanup system was tested in the towing configuration and operational configuration.

Experimental Validation of Fluid-Structure Interaction Co-Simulations Using ANSYS via Wind Tunnel Testing of Cantilevered Plate

2020 ◽  
Author(s):  
Thomas G. Shepard ◽  
Kyle Schneider ◽  
Sarah Baxter ◽  
William Schwartz
Keyword(s):  
Wind Tunnel ◽  
Computational Models ◽  
Fluid Structure Interaction ◽  
Mapping Method ◽  
The Body ◽  
Image Correlation ◽  
Turbulence Theory ◽  
Courant Number ◽  
Fluid Structure ◽  
Structure Interaction

Abstract Validation of numerical simulations is a key step in gaining confidence in the fidelity of computational models for a given application. These simulations take on additional complexity in fluid structure interactions when the body being studied experiences flow-induced deformation. In this study, experiments are conducted on a cantilevered aluminum plate mounted in a wind tunnel. Experimentally, deflections are measured using Digital Image Correlation and axial bending strains are measured using strain gages and. These values are compared to a coupled fluid-structure interaction simulation, which co-simulated the structural (Lagrangian FEA) and fluid (Navier-Stokes CFD) computational methods. Within the simulations, FEA parameters including mesh size, mapping method, and mesh type were varied; CFD parameters that were varied include turbulence theory, mesh sizing, inflation layer, mapping method, and Courant Number. Values were varied to study their effects on the simulation solution, as well as to ensure mesh independence of the solution relative to both simulation domains. Experiments were conducted on an Aluminum (6061-T6) plate measuring 152.4 × 50.8 × 0.61 mm. The plate was positioned in the wind tunnel at two different angles relative to the oncoming flow and Reynolds numbers of 98,000–247,000 were considered. The numerical simulation demonstrates agreement with DIC displacements and good agreement with measured strains with deflections up to ∼ 11 mm. Future steps are discussed.

scholarly journals 3D Fluid-Structure Interaction Experiment and Benchmark Results

PAMM ◽  
2016 ◽  
Vol 16 (1) ◽  
pp. 451-452 ◽  
Author(s):  
Andreas Hessenthaler ◽  
Stephanie Friedhoff ◽  
Oliver Röhrle ◽  
David A. Nordsletten
Keyword(s):  
Fluid Structure Interaction ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Interaction Experiment

scholarly journals A Thin Film Fluid Structure Interaction Model for the Study of Flexible Structure Dynamics in Centrifugal Pumps

2018 ◽  
Vol 141 (6) ◽  
Author(s):  
A. Albadawi ◽  
M. Specklin ◽  
R. Connolly ◽  
Y. Delauré
Keyword(s):  
Structural Model ◽  
Fluid Structure Interaction ◽  
Flexible Structures ◽  
Image Correlation ◽  
Structural Deformation ◽  
Immersed Boundary ◽  
Detached Eddy Simulation ◽  
Centrifugal Pumps ◽  
Fluid Structure ◽  
Structure Interaction

This paper describes a fluid-structure interaction (FSI) model for the study of flexible cloth-like structures or the so-called rags in flows through centrifugal pumps. The structural model and its coupling to the flow solver are based on a Lagrangian formulation combining structural deformation and motion modeling coupled to a sharp interface immersed boundary model (IBM). The solution has been implemented in the open-source library OpenFOAM relying in particular on its PIMPLE segregated Navier–Stokes pressure–velocity coupling and its detached eddy simulation (DES) turbulence model. The FSI solver is assessed in terms of its capability to generate consistent deformations and transport of the immersed flexible structures. Two benchmark cases are covered and both involve experimental validation with three-dimensional (3D) structural deformations of the rag captured using a digital image correlation (DIC) technique. Simulations of a rag transported in a centrifugal pump confirm the suitability of the model to inform on the dynamic behavior of immersed structures under practical engineering conditions.

scholarly journals The Sliding and Overturning Analysis of Spent Fuel Storage Rack Based on Dynamic Analysis Model

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Yu Liu ◽  
Daogang Lu ◽  
Yuanpeng Wang ◽  
Hongda Liu
Keyword(s):  
Impact Force ◽  
Fluid Structure Interaction ◽  
Seismic Loading ◽  
Spent Fuel ◽  
Analysis Model ◽  
Fem Model ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Fuel Storage ◽  
Interaction Experiment

Spent fuel rack is the key equipment for the storage of spent fuel after refueling. In order to investigate the performance of the spent fuel rack under the earthquake, the phenomena including sliding, collision, and overturning of the spent fuel rack were studied. An FEM model of spent fuel rack is built to simulate the transient response under seismic loading regarding fluid-structure interaction by ANSYS. Based on D’Alambert’s principle, the equilibriums of force and momentum were established to obtain the critical sliding and overturning accelerations. Then 5 characteristic transient loadings which were designed based on the critical sliding and overturning accelerations were applied to the rack FEM model. Finally, the transient displacement and impact force response of rack with different gap sizes and the supporting leg friction coefficients were analyzed. The result proves the FEM model is applicable for seismic response of spent fuel rack. This paper can guide the design of the future’s fluid-structure interaction experiment for spent fuel rack.

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