# Fluid Structure Interaction Modelling of Tidal Turbine Performance and Structural Loads in a Velocity Shear Environment

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## Abstract

**:**

## 1. Introduction

## 2. Modeling Approach

#### 2.1. Transient CFD Model Setup

#### 2.2. FEA Model Setup

#### 2.3. System Coupling Setup

^{−4}to provide the fluid force exerted on the rotor region. The FEA system is then started by the system coupling and the force data is transferred to the specified fluid solid interface region in the structural model to obtain a converged solution of the displacement data. The displacement data is transferred back to CFD module. The system coupling performs mesh deformation with the selected mesh deformation settings. The process is iterated for the number of defined coupling iterations till the completion of all the coupling steps.

## 3. Results and Discussion

#### 3.1. Development of the FSI Model

_{P}with an error of 4.8% with the experimental data compared to an error of 9.8% by the rigid body steady state CFD and one-way coupled FSI model. These results are also in accordance with the physical observation that the performance of the turbine will decrease as its blade are deformed. The thrust force is the other most important parameter that needs to be accurately predicted for the determination of flap wise bending. A similar plot for the thrust coefficient could have been very useful but the experimental data for thrust force was not available. Table 1 clearly shows that the difference in thrust prediction is negligible for all the FSI simulation and a clear reduction in the computational time has been achieved without any compromise on the fidelity of the solution.

#### 3.2. Effect of Velocity Profile on Performance and Structural Loads

## 4. Conclusions and Prospects

## Author Contributions

## Funding

## Acknowledgments

## Conflicts of Interest

## References

- Badshah, M.; Badshah, S.; Khalil, S.J. Hydrodynamic design of tidal current turbine and the effect of solidity on performance. J. Eng. Appl. Sci.
**2017**, 36, 45–54. [Google Scholar] - Batten, W.; Bahaj, A.; Molland, A.; Chaplin, J. The prediction of the hydrodynamic performance of marine current turbines. Renew. Energy
**2008**, 33, 1085–1096. [Google Scholar] [CrossRef] - Masters, I.; Chapman, J.; Willis, M.; Orme, J. A robust blade element momentum theory model for tidal stream turbines including tip and hub loss corrections. J. Mar. Eng. Technol.
**2011**, 10, 25–35. [Google Scholar] - Mujahid, B.; VanZwieten, J.H.; Saeed, B.; Sakhi, J. A CFD study of blockage ratio and boundary proximity effects on the performance of a tidal turbine. IET Renew. Power Gen. under review.
- Nitin, K.; Arindam, B. Performance characterization and placement of a marine hydrokinetic turbine in a tidal channel under boundary proximity and blockage effects. Appl. Energy
**2015**, 148, 121–133. [Google Scholar] [CrossRef] - Tatum, S.; Allmark, M.; Frost, C.; O’Doherty, D.; Mason-Jones, A.; O’Doherty, T. CFD modelling of a tidal stream turbine subjected to profiled flow and surface gravity waves. Int. J. Mar. Energy
**2016**, 15, 156–174. [Google Scholar] [CrossRef] - Tian, W.; VanZwieten, J.H.; Pyakurel, P.; Li, Y. Influences of yaw angle and turbulence intensity on the performance of a 20 kW in-stream hydrokinetic turbine. Energy
**2016**, 111, 104–116. [Google Scholar] [CrossRef] [Green Version] - Liu, J.; Lin, H.; Purimitla, S.R.; ET, M.D. The effects of blade twist and nacelle shape on the performance of horizontal axis tidal current turbines. Appl. Ocean Res.
**2017**, 64, 58–69. [Google Scholar] [CrossRef] - Nicholls-Lee, R.F. Adaptive Composite Blades for Horizontal Axis Tidal Turbines. Ph.D. Thesis, University of Southampton, Southampton, UK, 2011. [Google Scholar]
- Grogan, D.M.; Leen, S.B.; Kennedy, C.; Brádaigh, C.Ó. Design of composite tidal turbine blades. Renew. Energy
**2013**, 57, 151–162. [Google Scholar] [CrossRef] [Green Version] - Zhou, F.; Mahfuz, H.; Alsenas, G.M.; Hanson, H.P. Static and fatigue analysis of composite turbine blades under random ocean current loading. Mar. Technol. Soc. J.
**2013**, 47, 59–69. [Google Scholar] [CrossRef] - Turnock, S.; Wright, A. Directly coupled fluid structural model of a ship rudder behind a propeller. Mar. Struct.
**2000**, 13, 53–72. [Google Scholar] [CrossRef] - Nicholls-Lee, R.F.; Turnock, S.R.; Boyd, S.W. Simulation Based Optimization of Marine Current Turbine Blades. In Proceedings of the 7th International Conference on Computer and IT Applications in the Maritime Industries (COMPIT’08), Liège, Belgium, 21–23 April 2008; pp. 314–328. [Google Scholar]
- Kim, B.; Bae, S.; Kim, W.; Lee, S.; Kim, M. A Study on the Design Assessment of 50 kW Ocean Current Turbine Using Fluid Structure Interaction Analysis. In Proceedings of the IOP Conference Series: Earth and Environmental Science, Beijing, China, 19–23 August 2012; p. 042037. [Google Scholar]
- Jo, C.-H.; Kim, D.-Y.; Rho, Y.-H.; Lee, K.-H.; Johnstone, C. FSI analysis of deformation along offshore pile structure for tidal current power. Renew. Energy
**2013**, 54, 248–252. [Google Scholar] [CrossRef] [Green Version] - Nicholls-Lee, R.; Turnock, S.; Boyd, S. Application of bend-twist coupled blades for horizontal axis tidal turbines. Renew. Energy
**2013**, 50, 541–550. [Google Scholar] [CrossRef] - Tatum, S.; Frost, C.; Allmark, M.; O’Doherty, D.; Mason-Jones, A.; Prickett, P.; Grosvenor, R.; Byrne, C.; O’Doherty, T. Wave-current interaction effects on tidal stream turbine performance and loading characteristics. Int. J. Mar. Energy
**2016**, 14, 161–179. [Google Scholar] [CrossRef] - Craig, H.; Vincent, S.N.; Budi, G.; Michele, G.; Fotis, S. U.S. Department of Energy Reference Model Program RM1: Experimental Results. Technical Report; 2014. Available online: https://www.osti.gov/biblio/1172793-department-energy-reference-model-program-rm1-experimental-results (accessed on 5 July 2018). [CrossRef] [Green Version]
- ANSYS Inc. ANSYS CFX-Solver Modelling Guide; ANSYS, Inc.: Canonsburg, PA, USA, 2016; p. 170. [Google Scholar]
- Ageze, M.B.; Hu, Y.; Wu, H. Comparative Study on Uni-and Bi-Directional Fluid Structure Coupling of Wind Turbine Blades. Energies
**2017**, 10, 1499. [Google Scholar] [CrossRef] - Morris, C.E.; O’Doherty, D.M.; O’Doherty, T.; Mason-Jones, A. Kinetic energy extraction of a tidal stream turbine and its sensitivity to structural stiffness attenuation. Renew. Energy
**2016**, 88, 30–39. [Google Scholar] [CrossRef] - Morris, C. Influence of Solidity on the Performance, Swirl Characteristics, Wake Recovery and Blade Deflection of a Horizontal Axis Tidal Turbine. Ph.D. Thesis, Cardiff University, Wales, UK, 2014. [Google Scholar]
- Mason-Jones, A. Performance Assessment of a Horizontal Axis Tidal Turbine in a High Velocity Shear Environment. Ph.D. Thesis, Cardiff University, Wales, UK, 2009. [Google Scholar]

**Figure 5.**Contour plots of equivalent stress and total deformation on rotor at the last time step from the three FSI simulations.

**Figure 7.**Contours of Equivalent (Von-Mises) stress and Total deformation for rotor for uniform and profiled flow.

S# | Simulation Name | Computational Time (h) | Thrust Force (N) |
---|---|---|---|

1 | Two-way two turbine rotations | 283.3 | 99.29 |

2 | Two-way one turbine rotation | 105.6 | 98.66 |

3 | One-way one turbine rotation | 58.3 | 100.24 |

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**MDPI and ACS Style**

Badshah, M.; Badshah, S.; Kadir, K.
Fluid Structure Interaction Modelling of Tidal Turbine Performance and Structural Loads in a Velocity Shear Environment. *Energies* **2018**, *11*, 1837.
https://doi.org/10.3390/en11071837

**AMA Style**

Badshah M, Badshah S, Kadir K.
Fluid Structure Interaction Modelling of Tidal Turbine Performance and Structural Loads in a Velocity Shear Environment. *Energies*. 2018; 11(7):1837.
https://doi.org/10.3390/en11071837

**Chicago/Turabian Style**

Badshah, Mujahid, Saeed Badshah, and Kushsairy Kadir.
2018. "Fluid Structure Interaction Modelling of Tidal Turbine Performance and Structural Loads in a Velocity Shear Environment" *Energies* 11, no. 7: 1837.
https://doi.org/10.3390/en11071837