Wave Interaction with Large Submerged Objects

Garrison, C. J.; Rao, V. Seetharama; Snider, Robert H.

doi:10.4043/1278-ms

Cited by 13 publications

(7 citation statements)

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“…The formulation of the problem set up within the framework of two-dimensional linear diffraction theory, has been stated previously" but is presented here in a summary form for completeness (equations (1)- (9)). Under the assumptions of potential flow, small wave amplitude, and a direction of wave propagation that is normal to the longitudinal axis of the object a linearized harmonic velocity potential @(x, y, t ) is introduced as the real part of a complex function in the form where +(x, y) is the spatial velocity potential and (+ is the incident wave frequency such that u = 2 r / T in which T is the period of motion.…”

Section: Formulation Of the Boundary-value Problemmentioning

confidence: 99%

On the interactions of surface waves with immersed structures

Bird¹,

Shepherd

1984

Numerical Methods in Fluids

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SUMMARYThe fluid forces resulting from wave interaction with large submerged structures may be calculated using numerical procedures based on the solution of the associated boundary-value problem. In this paper, the analysis of wave interaction with a fixed submerged object of arbitrary cross-section and infinite length using a two-dimensional boundary value formation based on linear diffraction theory is summarized. Subsequently, the application of the boundary element method to obtain a solution is presented. The numerical considerations are emphasized with particular reference to computational efficiency.Numerical results are presented in the form of dimensionless wave force plots for various structural shapes. In the case of a bottom-seated half cylinder, for which there exists a closed-form solution, comparisons are made between results generated using both boundary element and equivalent finite element approaches. In the case of a submerged cylinder, comparisons are made between boundary element derived values and experimental results. The boundary element results compare well with both the closed-form solution and the experimental values.

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Section: Formulation Of the Boundary-value Problemmentioning

confidence: 99%

On the interactions of surface waves with immersed structures

Bird¹,

Shepherd

1984

Numerical Methods in Fluids

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“…During the numerical simulation, the parameters of the multi-type floating bodies are as follows: the length of horizontal rectangular a is 0.3 m, the length along the wave direction of horizontal rectangular b is 0.3 m, the height of horizontal rectangular c is 0.5 m, the radius of vertical cylinder R is 0.3 m, the height of vertical cylinder l is 0.5 m, the radius of sphere R is 0.3 m, the mean immersion depth is 0.15 m, the Underwater PTO damping coefficient in the vertical direction B z PTO is 20 KNs/m, and the mass of the novel heaving point absorber m is 10 kg. According to the model test results of previous research [51][52][53], the diffraction correction coefficient in the vertical direction C V of horizontal rectangular, vertical cylinder, and sphere can be obtained, respectively.…”

Section: Numerical Resultsmentioning

confidence: 99%

Energy Efficiency Analysis of Multi-Type Floating Bodies for a Novel Heaving Point Absorber with Application to Low-Power Unmanned Ocean Device

et al. 2018

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Long-term energy supplies hinder the application of the low-power unmanned ocean devices to the deep sea. Ocean wave energy is a renewable resource with amount stores of enormous and high density. The wave energy converter (WEC) could be miniaturized so that it can be integrated into the devices to make up the power module. In this paper, a small novel heaving point absorber of energy supply for low-power unmanned ocean devices is developed based on the counter-rotating self-adaptive mechanism. The floating body as an important part of the heaving point absorber, the geometric parameters is optimized to increase the efficiency of power production. Through constructing the constitutive relation between the geometric parameters, the wave force, the motion displacement, the motion velocity, and the capture width ratio of the floating body, the energy efficiency characteristics of the multi-type floating bodies are calculated, and the optimal shape is selected. On the other hand, in the calculation process of the wave force, the Froude-Krylov method is an effective method to accurately calculate the wave excitation force. Meanwhile, nonlinear static and dynamic Froude-Krylov force effectively overcomes the inaccuracy of the linear models and reduces the time consumed to simulate. Finally, the wave force, heaving velocity, heaving displacement, and capture width ratio of the three floating bodies are compared and analyzed, and the results show that the cylindrical floater that is vertically placed on the wave surface is more suitable for the novel heaving wave energy point absorber.

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“…is the immersed volume of the cylinder in the presence of a wave as a function of time t. It should be noted that Dixon et al (1979) ignored the drag term in equation 21since it was shown by Garrison and Rao (1971) that this term is small when the cylinder diameter is large compared with the wave amplitude. Dixon et al (1979) and Dixon (1980) used equation 21to derive an approximate formula for the vertical force of a partially submerged horizontal cylinder in deep water in which the centre of the cylinder is at any position above or below the still water line.…”

Section: Forces Induced On a Fixed Semi-immersed Horizontal Cylinder mentioning

confidence: 99%

Simulation and analysis of wave-structure interactions for a semi-immersed horizontal cylinder

et al. 2018

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The paper is concerned with the use of the open source computational fluid dynamics software package, OpenFOAM® for predicting and analysing the behaviour of a semiimmersed horizontal cylinder subject to different types of ocean wave conditions. This study involves two separate cases of wave-structure interaction involving a semi-immersed horizontal cylinder, which may represent the simplified form of a cylindrical component of a wave energy converter. First, the flow around a fixed semi-immersed horizontal cylinder subject to regular waves is studied, in which the horizontal and vertical forces are computed and compared to linear wave theory and available experimental data. Further, a semiimmersed horizontal cylinder with a prescribed oscillatory vertical motion is considered to determine the surface wave elevations generated by the motion of the cylinder. The measured numerical surface elevations are also compared with theoretical predictions and experimental data. Both cases considered in this paper are simulated in a numerical wave tank where wave relaxation zones are utilised to avoid wave reflections. It is concluded that the numerical data produced by OpenFOAM® provide good overall agreement within the limitations of the relevant theory and experiment data.

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Wave Interaction with Large Submerged Objects

Cited by 13 publications

References 0 publications

On the interactions of surface waves with immersed structures

On the interactions of surface waves with immersed structures

Energy Efficiency Analysis of Multi-Type Floating Bodies for a Novel Heaving Point Absorber with Application to Low-Power Unmanned Ocean Device

Simulation and analysis of wave-structure interactions for a semi-immersed horizontal cylinder

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