Comparison of Experimental and Numerical Model Results of Oscillating Water Column System Under Regular Wave Conditions


Wave energy has attracted significant attention because of its non-polluting nature, environment friendliness, low operational cost and simple maintenance procedures compared to other clean energy sources. In this study, it was attempted to optimize an oscillating water column (OWC) wave energy converter, which is constructed on a shoreline. This study proposed numerical and physical models for the optimization of the OWC-type wave energy converters. Sixty-four experimental sets were carried out by a piston-type wave maker in order to investigate the influence of wave parameters, water depth and geometry of coastal structures on the efficiency of the system. A numerical model of the experimental model sets of the OWC system was performed by a software called Flow 3D. Intersection with a water–air in the software for the determination of the free surface of a volume of fluid method is used. Kε turbulence model was used for turbulent model. The drag coefficient, surface roughness, pipe roughness and surface tension were used for calibration. It is observed that the numerical model results follow the experimental model results. The numerical and the experimental model results were compared with each other by taking into consideration the mean squared error, coefficient of determination (R2) and Nash–Sutcliffe efficiency (NSE) as performance evaluation criteria. According to the test results, the NSE value was obtained to be 0.97 and this value also shows very good agreement between numerical results and experimental results. The experimental results showed that wave parameters are strongly related to the outflow of air from the chamber, whereas the slope angle of the chamber is inversely related. Considering different water depths, the various wave series and angle of the chamber, maximum efficiency of OWC was obtained at 50 cm, wave series No. 1 and an angle of 40°, respectively.

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Computational fluid dynamics


Fractional area/volume obstacle representation


Land installed marine powered energy transformer




Mean square error


Nash–Sutcliffe coefficient


Oscillating water column


Reynolds-averaged Navier–Stokes


Resonant wave energy converter


Volume of fluid

A :

The cross-sectional area of the outflow air tube

A x :

Fractional area at the centers of cell faces normal to the x-direction

A y :

Fractional area at the centers of cell faces normal to the y-direction

A z :

Fractional area at the centers of cell faces normal to the z-direction

C1ε, C2ε, C3ε :

Constant values

D :

Diameter of air outflow tube


Diffusion term

d :

Water depth

E :

Mean air velocity from the results of experimental model

\(\bar{E}\) :

Mean of E values

e :

Height of opening of the OWC front wall

F :

Fraction of fluid in each cell

f x :

Viscous acceleration in x-direction

f y :

Viscous acceleration in y-direction

f z :

Viscous acceleration in z-direction

G k :

Buoyancy production term

G x :

Body accelerations in the x-direction

G y :

Body accelerations in the y-direction

G z :

Body accelerations in the z-direction

H :

Incident wave height

k :

Kinetic energy of turbulent

L :


N :

Mean air velocity from the results of numerical model

\(\mathop N\limits^{ - }\) :

Mean of N values

P :


P k :

Turbulent kinetic energy production

P owc :

Power of output air

Q :

Air discharge

R 2 :

Coefficient of determination

Re :

Reynolds number


Mass source

T :

Wave period

t :


u :

Velocity component in x-direction

V :

Velocity of air flow

v :

Velocity component in y-direction

V f :

Volumetric fluid fraction in each cell

w :

Velocity component in z-direction

X :

Front wall length of oscillating water column system

x :

Coordinate in x-direction

x max :

Downstream boundary condition

x min :

Upstream boundary condition

y :

Coordinate in y-direction

Z :

Elevation head

z :

Coordinate in z-direction (m)

z max :

Upper limit of the solution

z min :

Base wall

α :

Front wall angle of oscillating water column system

γ :

Specific weight

ΔP :

Differential pressure

ε :

Dissipation rate of turbulent kinetic energy (kε model)

µ a :

Dynamic viscosity of air

ρ :


ρ a :

Density of air

ρ w :

Density of water

ω :

Specific dissipation rate of turbulent kinetic energy (k − ω model)


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This research was funded by TUBITAK (The Turkish National Science and Technology Foundation) under the Grant Number 112M413. The authors are grateful to TUBITAK for supporting our study.

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Correspondence to Farrokh Mahnamfar.

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Mahnamfar, F., Altunkaynak, A. & Abdollahzadehmoradi, Y. Comparison of Experimental and Numerical Model Results of Oscillating Water Column System Under Regular Wave Conditions. Iran J Sci Technol Trans Civ Eng 44, 299–315 (2020).

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  • Wave energy
  • Wave energy converters
  • Experimental testing
  • Numerical modeling
  • Performance evaluation criteria
  • OWC