Research Papers: Ocean Renewable Energy

Unsteady RANS Simulations of Wells Turbine Under Transient Flow Conditions

[+] Author and Article Information
Qiuhao Hu

Multifunctional Ship Model Towing Tank,
School of Naval Architecture
Ocean & Civil Engineering,
Shanghai Jiao Tong University,
800 Dongchuan Road,
Shanghai 201100, China
e-mail: huecu588755@sjtu.edu.cn

Ye Li

Multifunctional Ship Model Towing Tank,
School of Naval Architecture
Ocean & Civil Engineering,
Shanghai Jiao Tong University,
800 Dongchuan Road,
Shanghai 201100, China
e-mail: ye.li@sjtu.edu.cn

1Corresponding author.

Contributed by the Ocean, Offshore, and Arctic Engineering Division of ASME for publication in the JOURNAL OF OFFSHORE MECHANICS AND ARCTIC ENGINEERING. Manuscript received January 23, 2017; final manuscript received August 11, 2017; published online September 29, 2017. Assoc. Editor: Ould el Moctar.

J. Offshore Mech. Arct. Eng 140(1), 011901 (Sep 29, 2017) (11 pages) Paper No: OMAE-17-1015; doi: 10.1115/1.4037696 History: Received January 23, 2017; Revised August 11, 2017

This paper presents our recent numerical simulations of a high-solidity Wells turbine under both steady and unsteady conditions by solving Reynolds-averaged Navier–Stokes (RANS) equations. For steady conditions, the equations are solved in a reference frame with the same angular velocity of the turbine. Good agreement between numerical simulation result and experimental data has been obtained in the operational region and incipient stall conditions. The exact value of stall point has been accurately predicted. Through analyzing the detailed fluid fields, we find that the stall occurs near the tip of the blade while the boundary layer keeps attached near the hub, due to the effect of radial flow. For unsteady conditions, two types of control methods are studied: constant angular velocity and constant damping moment. For the constant angular velocity, the behaviors of the turbine under both high and low sea wave frequency are calculated to compare with those obtained by quasi-steady method. The hysteresis characteristic can be observed and deeply affects the behaviors of the Wells turbine with high wave frequency. For the constant damping moment, the turbine angular velocity is time dependent. Under sinusoidal flow, the incident flow velocity in the operational region can be improved to avoid the stall.

Copyright © 2018 by ASME
Your Session has timed out. Please sign back in to continue.


Falnes, J. , 2002, Ocean Waves and Oscillating Systems: Linear Interactions Including Wave-Energy Extraction, Cambridge University Press, Cambridge, UK. [CrossRef]
Li, Y. , and Yu, Y.-H. , 2012, “ A Synthesis of Numerical Methods for Modeling Wave Energy Converter-Point Absorbers,” Renewable Sustainable Energy Rev., 16(6), pp. 4352–4364. [CrossRef]
Evans, D. V. , 1978, “ The Oscillating Water Column Wave-Energy Device,” IMA J. Appl. Math., 22(4), pp. 423–433. [CrossRef]
Lee, C.-H. , Newman, J. N. , and Nielsen, F. G. , 1996, “ Wave Interactions With an Oscillating Water Column,” Sixth International Offshore and Polar Engineering Conference, Los Angeles, CA, May 26–31, SPE Paper No. ISOPE-I-96-013.
Whittaker, T. J. T. , Leitch, J. G. , Long, A. E. , and Murray, M. , 1985, “ The Q. U. B.(Queen's University of Belfast) Axisymmetric and Multi-Resonant Wave Energy Convertors,” ASME J. Energy Resour. Technol., 107(1), pp. 74–80. [CrossRef]
Raghunathan, S. , 1995, “ The Wells Air Turbine for Wave Energy Conversion,” Prog. Aerosp. Sci., 31(4), pp. 335–386. [CrossRef]
Curran, R. , Stewart, T. P. , and Whittaker, T. J. T. , 1997, “ Design Synthesis of Oscillating Water Column Wave Energy Converters: Performance Matching,” Proc. Inst. Mech. Eng. Part A, 211(6), pp. 489–505. [CrossRef]
Brito-Melo, A. , Gato, L. M. C. , and Sarmento, A. J. N. A. , 2002, “ Analysis of Wells Turbine Design Parameters by Numerical Simulation of the OWC Performance,” Ocean Eng., 29(12), pp. 1463–1477. [CrossRef]
Setoguchi, T. , Kim, T. W. , Takao, M. , Thakker, A. , and Raghunathan, S. , 2004, “ The Effect of Rotor Geometry on the Performance of a Wells Turbine for Wave Energy Conversion,” Int. J. Ambient Energy, 25(3), pp. 137–150. [CrossRef]
Suzuki, M. , and Arakawa, C. , 2008, “ Influence of Blade Profiles on Flow Around Wells Turbine,” Int. J. Fluid Mach. Syst., 1(1), pp. 148–154. [CrossRef]
Thakker, A. , and Dhanasekaran, T. S. , 2004, “ Computed Effects of Tip Clearance on Performance of Impulse Turbine for Wave Energy Conversion,” Renewable Energy, 29(4), pp. 529–547. [CrossRef]
Takao, M. , Setoguchi, T. , Kinoue, Y. , and Kaneko, K. , 2007, “ Wells Turbine With End Plates for Wave Energy Conversion,” Ocean Eng., 34(11), pp. 1790–1795. [CrossRef]
Folley, M. , Curran, R. , and Whittaker, T. , 2006, “ Comparison of Limpet Contra-Rotating Wells Turbine With Theoretical and Model Test Predictions,” Ocean Eng., 33(8), pp. 1056–1069. [CrossRef]
Gato, L. M. C. , and Falcao, A. F. D. O. , 1990, “ Performance of the Wells Turbine With a Double Row of Guide Vanes,” JSME Int. J. Ser. 2, Fluids Eng. Heat Transfer, Power, Combust. Thermophys. Properties, 33(2), pp. 265–271.
Dhanasekaran, T. S. , and Govardhan, M. , 2005, “ Computational Analysis of Performance and Flow Investigation on Wells Turbine for Wave Energy Conversion,” Renewable Energy, 30(14), pp. 2129–2147. [CrossRef]
Thakker, A. , Frawley, P. , and Bajeet, E. S. , 2001, “ Numerical Analysis of Wells Turbine Performance Using a 3D Navier-Stokes Explicit Solver,” 11th International Offshore and Polar Engineering Conference, Stavanger, Norway, June 17–22, SPE Paper No. ISOPE-I-01-090.
Kim, T. H. , Setoguchi, T. , Kaneko, K. , and Raghunathan, S. , 2002, “ Numerical Investigation on the Effect of Blade Sweep on the Performance of Wells Turbine,” Renewable Energy, 25(2), pp. 235–248. [CrossRef]
Torresi, M. , Camporeale, S. M. , and Pascazio, G. , 2009, “ Detailed CFD Analysis of the Steady Flow in a Wells Turbine Under Incipient and Deep Stall Conditions,” ASME J. Fluids Eng., 131(7), p. 071103. [CrossRef]
Hu, Q.-H. , Li, Y. , and Wei, F.-Y. , 2016, “ Preliminary Results of Numerical Simulations of a Bio-Mimetic Wells Turbine,” ASME Paper No. OMAE2016-54463.
Torresi, M. , Camporeale, S. M. , Strippoli, P. D. , and Pascazio, G. , 2008, “ Accurate Numerical Simulation of a High Solidity Wells Turbine,” Renewable Energy, 33(4), pp. 735–747. [CrossRef]
Inoue, M. , Kaneko, K. , Setoguchi, T. , and Shimamoto, K. , 1986, “ Studies on Wells Turbine for Wave Power Generator: 4th Report, Starting and Running Characteristics in Periodically Oscillating Flow,” Bull. JSME, 29(250), pp. 1177–1182. [CrossRef]
Goldstein, S. , 1929, “ On the Vortex Theory of Screw Propellers,” Proc. R. Soc. London Ser. A, 123(792), pp. 440–465. [CrossRef]
Newman, J. N. , 1977, Marine Hydrodynamics, MIT Press, Cambridge, MA.
Leishman, J. G. , 1990, “ Dynamic Stall Experiments on the NACA 23012 Aerofoil,” Exp. Fluids, 9(1–2), pp. 49–58. [CrossRef]
Mittal, S. , and Saxena, P. , 2002, “ Hysteresis in Flow Past a NACA 0012 Airfoil,” Comput. Methods Appl. Mech. Eng., 191(19), pp. 2207–2217. [CrossRef]
Lee, T. , and Gerontakos, P. , 2004, “ Investigation of Flow Over an Oscillating Airfoil,” J. Fluid Mech., 512, pp. 313–341. [CrossRef]
Ericsson, L. E. , and Reding, J. P. , 1988, “ Fluid Mechanics of Dynamic Stall—Part I: Unsteady Flow Concepts,” J. Fluids Struct., 2(1), pp. 1–33. [CrossRef]


Grahic Jump Location
Fig. 1

Illustration of the OWC system (Adapted from Li and Yu [2])

Grahic Jump Location
Fig. 2

Illustration of Wells turbine

Grahic Jump Location
Fig. 3

Definition of sweep ratio

Grahic Jump Location
Fig. 4

Near wall mesh conditions

Grahic Jump Location
Fig. 5

Computational domain (a) reference frame and (b) moving mesh

Grahic Jump Location
Fig. 6

Turbine torque results with respect to different grid numbers (a) reference frame and (b) moving mesh

Grahic Jump Location
Fig. 7

Comparison of numerical results and experimental data in steady condition: (a) torque coefficient, (b) pressure drop coefficient, and (c) efficiency

Grahic Jump Location
Fig. 8

Relative velocity contours downstream the blade: (a) ϕ = 0.24 and (b) ϕ = 0.28 (r = 135 mm)

Grahic Jump Location
Fig. 9

The pressure distribution along the chord in r = 135 mm

Grahic Jump Location
Fig. 10

Relative velocity contour downstream the blade

Grahic Jump Location
Fig. 11

(a) Axial velocity components and (b) radial velocity components versus different radii along the chord. The origin for the position is the vertical line through the hub center in Fig. 3.

Grahic Jump Location
Fig. 12

Stream line near the leading edge of the blades

Grahic Jump Location
Fig. 13

Hysteresis characteristic: (a) torque coefficient, for ϕ0 = 0.22, (b) torque coefficient, for ϕ0 = 0.26, (c) pressure drop coefficient, for ϕ0 = 0.22, and (d) pressure drop coefficient, for ϕ0 = 0.26

Grahic Jump Location
Fig. 14

Comparison of coefficients in acceleration process, decelerate process, and quasi-steady conditions: (a) mean torque coefficient and (b) mean pressure drop coefficient

Grahic Jump Location
Fig. 15

Comparison of (a) mean torque coefficient and (b) mean pressure drop coefficient in unsteady conditions in a whole period and quasi-steady conditions

Grahic Jump Location
Fig. 16

Angular velocity for T = 4 s and T = 8 s

Grahic Jump Location
Fig. 17

Angular velocity in the acceleration process (incident velocity improved from 19.129 m/s to 24.987 m/s in 0.88 s)

Grahic Jump Location
Fig. 18

Comparison of torque under steady and unsteady flows, for ϕ0 = 0.28

Grahic Jump Location
Fig. 19

Torque of two control methods under sinusoidal incident flow

Grahic Jump Location
Fig. 20

Comparison of the numerical results between moving mesh and reference frame

Grahic Jump Location
Fig. 21

Comparison of the numerical results between moving mesh and reference frame



Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In