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Dr. Ling Qian
Department of Computing and Mathematics, Manchester Metropolitan University, M1 5GD Manchester, UK

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Research Keywords & Expertise

0 Offshore Renewable Energy
0 wave structure interaction
0 Computational aerodynamics and hydrodynamics
0 Numerical wave tanks
0 Cartesian cut cell and overset grid

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Cartesian cut cell and overset grid
wave structure interaction

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Journal article
Published: 26 June 2021 in Ocean Engineering
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The severe sloshing induced by earthquake in cylindrical liquefied petroleum gas (LPG) storage tank is of great concern for liquid storage design. For suppressing sloshing, porous material attached to inner periphery of the tank wall is proposed and studied numerically by using OpenFOAM. The model was validated against with the available data of sloshing in cylindrical tank without and with ring baffle, and flow through porous media in a U-tube and porous dam break. Fair agreements between them are obtained. Findings show that damping effects of porous material layer was significant in linear sloshing scenario compared with ring baffle. The porous material layer was also proved to be good pressure absorber and energy dissipator as evidenced in pressure distribution and evolution of velocity and kinetic energy. Under 1-D harmonic excitation, nonlinear swirling waves could be effectively changed into planar waves due to the effects of porous material layer inside cylindrical tank. As a demonstration, sloshing damping effects of porous material layer in a real scale upright cylindrical tank under EL-centro earthquake excitation were investigated numerically.

ACS Style

Mi-An Xue; Zhouyu Jiang; Pengzhi Lin; Jinhai Zheng; Xiaoli Yuan; Ling Qian. Sloshing dynamics in cylindrical tank with porous layer under harmonic and seismic excitations. Ocean Engineering 2021, 235, 109373 .

AMA Style

Mi-An Xue, Zhouyu Jiang, Pengzhi Lin, Jinhai Zheng, Xiaoli Yuan, Ling Qian. Sloshing dynamics in cylindrical tank with porous layer under harmonic and seismic excitations. Ocean Engineering. 2021; 235 ():109373.

Chicago/Turabian Style

Mi-An Xue; Zhouyu Jiang; Pengzhi Lin; Jinhai Zheng; Xiaoli Yuan; Ling Qian. 2021. "Sloshing dynamics in cylindrical tank with porous layer under harmonic and seismic excitations." Ocean Engineering 235, no. : 109373.

Journal article
Published: 21 May 2021 in Ocean Engineering
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A new three-dimensional immersed boundary method combined with the level set method for the interface capturing is developed to simulate the interaction between the fixed∖moving structure and the two-phase fluid flow. The concept of the forcing point searching scheme developed for the two-dimensional situations in Yan et al. (2018) is extended in the present study to three dimensions, where the determination of intersections between the arbitrary body surface and the Cartesian background grid system is the major issue. This problem can be converted to the prediction of triangle–triangle intersection, which was traditionally solved from the geometrical point of view. Here, an algebraic algorithm is adopted for the triangle–triangle intersection, based on which the forcing points can be determined in the three-dimensional immersed boundary method. This algebraic algorithm is robust for any body geometry and easy for implementation. To demonstrate the accuracy and capability of the developed numerical model, three benchmark testing cases for water impact problems are conducted, including dam break over a fixed obstacle, water entry of a wedge and free decay of a bobber. Extensive comparisons with the experimental data and the numerical results obtained by other immersed boundary methods suggest that the developed immersed boundary method is accurate and effective for both fixed and moving bodies with complex geometries.

ACS Style

Bin Yan; Wei Bai; Sheng-Chao Jiang; Peiwen Cong; Dezhi Ning; Ling Qian. A three-dimensional immersed boundary method based on an algebraic forcing-point-searching scheme for water impact problems. Ocean Engineering 2021, 233, 109189 .

AMA Style

Bin Yan, Wei Bai, Sheng-Chao Jiang, Peiwen Cong, Dezhi Ning, Ling Qian. A three-dimensional immersed boundary method based on an algebraic forcing-point-searching scheme for water impact problems. Ocean Engineering. 2021; 233 ():109189.

Chicago/Turabian Style

Bin Yan; Wei Bai; Sheng-Chao Jiang; Peiwen Cong; Dezhi Ning; Ling Qian. 2021. "A three-dimensional immersed boundary method based on an algebraic forcing-point-searching scheme for water impact problems." Ocean Engineering 233, no. : 109189.

Journal article
Published: 01 March 2021 in Proceedings of the Institution of Civil Engineers - Engineering and Computational Mechanics
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This work contributes to the CCP-WSI Blind Test Series 2 by numerically investigating the dynamic response of two simplified point absorber wave energy converters (a hemispherical-bottom cylinder and a cylinder with moon-pool) under the action of focused waves of varying steepness. The open source toolbox OpenFOAM along with its new overset grid functionality is applied and evaluated for the complex flow problem involving both large free surface deformations and large amplitude motions of floating objects. The quality of the numerically generated focused wave groups is first examined and validated against the experimental data. The effects of both wave steepness and the moon-pool on the dynamic responses and mooring loads of the simplified wave energy converters (WECs) are then analyzed.

ACS Style

Zaibin Lin; Hao Chen; Ling Qian; Zhihua Ma; Derek Causon; Clive Mingham. Simulating focused wave impacts on point absorber wave energy converters. Proceedings of the Institution of Civil Engineers - Engineering and Computational Mechanics 2021, 174, 19 -31.

AMA Style

Zaibin Lin, Hao Chen, Ling Qian, Zhihua Ma, Derek Causon, Clive Mingham. Simulating focused wave impacts on point absorber wave energy converters. Proceedings of the Institution of Civil Engineers - Engineering and Computational Mechanics. 2021; 174 (1):19-31.

Chicago/Turabian Style

Zaibin Lin; Hao Chen; Ling Qian; Zhihua Ma; Derek Causon; Clive Mingham. 2021. "Simulating focused wave impacts on point absorber wave energy converters." Proceedings of the Institution of Civil Engineers - Engineering and Computational Mechanics 174, no. 1: 19-31.

Journal article
Published: 27 November 2020 in Applied Ocean Research
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A new Fully Nonlinear Potential Flow (FNPF) numerical model has been developed for the simulation of nonlinear water wave problems. At each time step, the mixed boundary value problem for the flow field is spatially discretised by Finite Volume Method (FVM) and the kinematic and dynamic free surface boundary conditions are defined in a semi-Eulerian-Lagrangian form, which are used to update the wave elevation and velocity potential on the free surface. In the numerical model, waves are generated through a relaxation zone and absorbed by an artificial damping zone at the inlet and outlet of the numerical wave tank (NWT), respectively. Instead of a five-point smoothing technique, a more versatile fourth-order technique is developed to eliminate the possible saw-tooth instability at the free surface. Test cases with increasing complexities, such as wave generation and absorption, 2- and 3-Dimensional wave shoaling, and wave-cylinder interaction are simulated to assess its accuracy, convergence, and robustness. For all the cases considered, satisfactory agreements of free surface elevation and wave-induced forces against the experimental measurements and other existing numerical results are achieved. The developed numerical model fully utilises the existing functionalities in OpenFOAM and has the potential to provide an effective alternative to other FNPF based models for constructing a hybrid numerical wave tank model through its coupling with the multiphase flow models in OpenFOAM.

ACS Style

Zaibin Lin; Ling Qian; Wei Bai; Zhihua Ma; Hao Chen; Jian-Guo Zhou; Hanbin Gu. A Finite Volume Based Fully Nonlinear Potential Flow Model for Water Wave Problems. Applied Ocean Research 2020, 106, 102445 .

AMA Style

Zaibin Lin, Ling Qian, Wei Bai, Zhihua Ma, Hao Chen, Jian-Guo Zhou, Hanbin Gu. A Finite Volume Based Fully Nonlinear Potential Flow Model for Water Wave Problems. Applied Ocean Research. 2020; 106 ():102445.

Chicago/Turabian Style

Zaibin Lin; Ling Qian; Wei Bai; Zhihua Ma; Hao Chen; Jian-Guo Zhou; Hanbin Gu. 2020. "A Finite Volume Based Fully Nonlinear Potential Flow Model for Water Wave Problems." Applied Ocean Research 106, no. : 102445.

Original paper
Published: 10 January 2020 in Nonlinear Dynamics
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A liquid storage container installed on the top of a fixed offshore platform is used as a tuned liquid damper (TLD) to suppress structural vibration through sloshing motion and viscous energy dissipation. To further optimize TLD capability on suppressing vibration and accurately predict nonlinear coupled processes between TLD and offshore platform, a two-way coupling numerical model was developed to investigate the nonlinear vibration of TLD and elastic supporting structural platform (SSP). Meanwhile, laboratory experiments of TLD interaction with the SSP were also conducted on a six-degree-of-freedom motion simulator to validate the developed model. The bottom plate of the SSP was fixed to the motion simulator and subjected to sinusoidal excitation in the horizontal direction. The natural frequency of bare SSP was obtained firstly by shaking table tests at a wide range of external excitation frequencies and finite element modal analysis. The developed numerical model was validated by using the present experimental data in terms of both the roof plate displacements of the SSP and the free surface elevation and waveforms in TLD. Effects of TLD in suppressing the nonlinear vibration of the elastic SSP were further investigated numerically by varying the mass and frequency ratio of TLD to the SSP. Wavelet transform was used to analyze the nonlinear interaction and energy distribution characteristics of the sloshing wave in TLD. It was shown that the peak displacement response of the roof plate had been significantly reduced, and at the same time a frequency shift occurred after TLD installed on the SSP. In addition, the sudden excitation breaks the balance of energy absorption and production in fluids, resulting in larger wave height. Finally, a mass ratio of 2% and a frequency ratio of 1 were found to be optimal by considering the frequency shift and energy dissipation.

ACS Style

Peng Dou; Mi-An Xue; Jinhai Zheng; Chi Zhang; Ling Qian. Numerical and experimental study of tuned liquid damper effects on suppressing nonlinear vibration of elastic supporting structural platform. Nonlinear Dynamics 2020, 99, 2675 -2691.

AMA Style

Peng Dou, Mi-An Xue, Jinhai Zheng, Chi Zhang, Ling Qian. Numerical and experimental study of tuned liquid damper effects on suppressing nonlinear vibration of elastic supporting structural platform. Nonlinear Dynamics. 2020; 99 (4):2675-2691.

Chicago/Turabian Style

Peng Dou; Mi-An Xue; Jinhai Zheng; Chi Zhang; Ling Qian. 2020. "Numerical and experimental study of tuned liquid damper effects on suppressing nonlinear vibration of elastic supporting structural platform." Nonlinear Dynamics 99, no. 4: 2675-2691.

Journal article
Published: 16 October 2019 in Ocean Engineering
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This paper presents a numerical study of oblique focused wave group generation and interaction with a fixed FPSO-shaped body, with thorough validations against available experimental data. The 3D numerical model is based on the open-source toolbox OpenFOAM®, where the oblique waves are generated using multiple virtual segmented wave paddles. The surface elevation and velocity profiles on each paddle are derived based on the snake principle, which mimics the behaviour of wave paddles in the physical wave tank. Numerical tests are firstly conducted for focused wave groups propagating obliquely in an empty wave tank using the proposed scheme. By analysis of the surface elevation, it is found that reasonably good quality of oblique wave fields can be generated in the central area of the wave basin. Furthermore, investigations are carried out on the effects of wave angles on the harmonic structures of the wave groups using the phase-inversion method. It is shown that while the wave angle has minor effects on the linear and second order harmonics, the third order harmonic is altered by the wave angles, albeit its magnitude is very small. Finally, to show the effectiveness of the numerical oblique wave generation method and the importance of the angle effects in the wave-structure interaction process, simulations are carried out for the oblique focused wave group interacting with a fixed FPSO-shaped body. The effects of the wave incidence angle are clearly shown from the comparison of the integrated wave forces between the cases with different wave propagating angles.

ACS Style

Hao Chen; Ling Qian; Wei Bai; Zhihua Ma; Zaibin Lin; Mi-An Xue. Oblique focused wave group generation and interaction with a fixed FPSO-shaped body: 3D CFD simulations and comparison with experiments. Ocean Engineering 2019, 192, 106524 .

AMA Style

Hao Chen, Ling Qian, Wei Bai, Zhihua Ma, Zaibin Lin, Mi-An Xue. Oblique focused wave group generation and interaction with a fixed FPSO-shaped body: 3D CFD simulations and comparison with experiments. Ocean Engineering. 2019; 192 ():106524.

Chicago/Turabian Style

Hao Chen; Ling Qian; Wei Bai; Zhihua Ma; Zaibin Lin; Mi-An Xue. 2019. "Oblique focused wave group generation and interaction with a fixed FPSO-shaped body: 3D CFD simulations and comparison with experiments." Ocean Engineering 192, no. : 106524.

Journal article
Published: 22 June 2018 in Ocean Engineering
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An immersed boundary method is applied to simulate the green water over a fixed deck by combining a level set method for the free water surface capturing. An efficient Navier-Stokes equation solver of second-order accuracy adopting the fractional step method at a staggered Cartesian grid system is used to solve the incompressible fluid motion. The numerical model is validated by comparing extensively the wave elevation and pressure with the experimental data for two types of fixed decks, which suggests that the developed immersed boundary method coupled with the level set method is very promising to predict green water problems due to its accuracy and efficiency. Furthermore, the cross-sectional velocity distribution over the deck, which is an important parameter in the industrial application, is computed and compared to the analytical Ritter's solution. It is found that Ritter's solution is much more conservative than the numerical simulations, which confirms the safe application of the simplified analytical solution in the current design practise. Volume of green water over the deck that affects the stability of deck is also tracked. The numerical results reveal that the amount of green water over both the two types of fixed decks shows a linear relationship with the relative wave height. This important finding may be very helpful for the prediction of deck elevation under a certain wave condition to reduce the occurrence of green water event.

ACS Style

Bin Yan; Wei Bai; Ling Qian; Zhihua Ma. Study on hydro-kinematic characteristics of green water over different fixed decks using immersed boundary method. Ocean Engineering 2018, 164, 74 -86.

AMA Style

Bin Yan, Wei Bai, Ling Qian, Zhihua Ma. Study on hydro-kinematic characteristics of green water over different fixed decks using immersed boundary method. Ocean Engineering. 2018; 164 ():74-86.

Chicago/Turabian Style

Bin Yan; Wei Bai; Ling Qian; Zhihua Ma. 2018. "Study on hydro-kinematic characteristics of green water over different fixed decks using immersed boundary method." Ocean Engineering 164, no. : 74-86.

Editorial
Published: 15 May 2018 in Mathematical Problems in Engineering
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ACS Style

Jian G. Zhou; Alistair Borthwick; Haifei Liu; Ling Qian. Advances in Numerical Techniques for Modelling Water Flows. Mathematical Problems in Engineering 2018, 2018, 1 -2.

AMA Style

Jian G. Zhou, Alistair Borthwick, Haifei Liu, Ling Qian. Advances in Numerical Techniques for Modelling Water Flows. Mathematical Problems in Engineering. 2018; 2018 ():1-2.

Chicago/Turabian Style

Jian G. Zhou; Alistair Borthwick; Haifei Liu; Ling Qian. 2018. "Advances in Numerical Techniques for Modelling Water Flows." Mathematical Problems in Engineering 2018, no. : 1-2.

Journal article
Published: 01 March 2018 in Ocean Engineering
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We introduce a dynamic-boundary numerical wave generation procedure developed for wave structure interaction (WSI) simulations typical of ocean and coastal engineering problems. This implementation relies on a dynamic mesh which deforms in order to replicate the motion of the wave-maker, and it is integrated in wsiFoam: a multi-region coupling strategy applied to two-phase Navier-Stokes solvers developed in our previous work [Martínez Ferrer et al. A multi-region coupling scheme for compressible and incompressible flow solvers for two-phase flow in a numerical wave tank. Computer & Fluids 125 (2016) 116–129]. The combination of the dynamic-boundary method with a multi-region mesh counteracts the increase in computational cost, which is intrinsic to simulations featuring dynamic domains. This approach results in a high performance computing wave generation strategy that can be utilised in a numerical wave tank to carry out accurate and efficient simulations of wave generation, propagation and interaction with fixed structures and floating bodies. We conduct a series of benchmarks to verify the implementation of this wave generation method and the capabilities of the solver wsiFoam to deal with wave structure interaction problems. These benchmarks include regular and focused waves, wave interaction with a floating body and the modelling of a wave energy converter, using different wave-maker geometries: piston, flap and plunger. The results gathered in this work agree well with experimental data measured in the laboratory and other numerical simulations.

ACS Style

Pedro J. Martínez-Ferrer; Ling Qian; Zhihua Ma; Derek M. Causon; Clive G. Mingham. Improved numerical wave generation for modelling ocean and coastal engineering problems. Ocean Engineering 2018, 152, 257 -272.

AMA Style

Pedro J. Martínez-Ferrer, Ling Qian, Zhihua Ma, Derek M. Causon, Clive G. Mingham. Improved numerical wave generation for modelling ocean and coastal engineering problems. Ocean Engineering. 2018; 152 ():257-272.

Chicago/Turabian Style

Pedro J. Martínez-Ferrer; Ling Qian; Zhihua Ma; Derek M. Causon; Clive G. Mingham. 2018. "Improved numerical wave generation for modelling ocean and coastal engineering problems." Ocean Engineering 152, no. : 257-272.

Journal article
Published: 01 March 2018 in International Journal of Offshore and Polar Engineering
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ACS Style

Pedro J Martínez-Ferrer; Ling Qian; Derek M Causon; Clive G Mingham; Zhihua Ma. Numerical Simulation of Wave Slamming on a Flap-Type Oscillating Wave Energy Device. International Journal of Offshore and Polar Engineering 2018, 28, 65 -71.

AMA Style

Pedro J Martínez-Ferrer, Ling Qian, Derek M Causon, Clive G Mingham, Zhihua Ma. Numerical Simulation of Wave Slamming on a Flap-Type Oscillating Wave Energy Device. International Journal of Offshore and Polar Engineering. 2018; 28 (1):65-71.

Chicago/Turabian Style

Pedro J Martínez-Ferrer; Ling Qian; Derek M Causon; Clive G Mingham; Zhihua Ma. 2018. "Numerical Simulation of Wave Slamming on a Flap-Type Oscillating Wave Energy Device." International Journal of Offshore and Polar Engineering 28, no. 1: 65-71.

Journal article
Published: 31 January 2018 in Computers & Fluids
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This paper extends a recently proposed multi-region based numerical wave tank (Martínez-Ferrer et al. [1]) to solve water entry problems in naval engineering. The original static linking strategy is developed to enable the dynamic coupling of several moving regions. This permits the method to deal with large-amplitude motions for structures slamming into water waves. A background grid and one or more component meshes are firstly generated to overlay the whole computational domain and the sub-domains surrounding the structures, respectively. During computation, the background mesh is fixed while the small grids move freely or as prescribed without deformation and regeneration. This effectively circumvents the large and often excessive error-prone dynamic deformation of a single-block mesh as well as the complex and time-consuming mesh regeneration. Test cases of dam breaking with and without obstacles are first conducted to verify the developed code by comparing the numerical solution against experimental data. Then the new code is used to solve prescribed and free-fall water entry problems. The obtained results agree well with experimental measurements and other computational results reported in the literature.

ACS Style

Z.H. Ma; Ling Qian; Pedro J. Martínez-Ferrer; D.M. Causon; C.G. Mingham; W. Bai. An overset mesh based multiphase flow solver for water entry problems. Computers & Fluids 2018, 172, 689 -705.

AMA Style

Z.H. Ma, Ling Qian, Pedro J. Martínez-Ferrer, D.M. Causon, C.G. Mingham, W. Bai. An overset mesh based multiphase flow solver for water entry problems. Computers & Fluids. 2018; 172 ():689-705.

Chicago/Turabian Style

Z.H. Ma; Ling Qian; Pedro J. Martínez-Ferrer; D.M. Causon; C.G. Mingham; W. Bai. 2018. "An overset mesh based multiphase flow solver for water entry problems." Computers & Fluids 172, no. : 689-705.

Journal article
Published: 09 October 2017 in Ocean Engineering
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This paper presents a numerical study of the gap resonance between two side-by-side barges by using a multiphase Navier-Stokes equations model. In order to verify the multiphase flow model, it is firstly applied to simulate a two-dimensional gap resonance problem for two fixed boxes under various wave conditions. A comparison of the free surface elevations obtained on successively refined grids confirms the mesh convergence of numerical solutions. The calculated wave elevation response amplitude operators (RAOs) in the gap compare well with the experimental measurements. The multiphase flow model is further extended to calculate a three-dimensional gap resonance problem for two adjacent rectangular barges. The computed free surface RAOs in the gap also agree well with the experimental results. A close examination of the flow velocity and vorticity in the gap region at the piston resonant mode reveals that large amount of vortices are generated by the sharp corners of the two barges and shed downwards, which provide an effective mechanism to dissipate the flow kinematic energy and to reduce the wave elevation in the gap. On the contrary, rounded corners are not able to induce the same level amount of vortices to dampen the gap resonance. The effects of incident wave steepness on the viscous damping associated with the twin-barge system are highlighted.

ACS Style

Xingya Feng; W. Bai; X.B. Chen; Ling Qian; Zhihua Ma. Numerical investigation of viscous effects on the gap resonance between side-by-side barges. Ocean Engineering 2017, 145, 44 -58.

AMA Style

Xingya Feng, W. Bai, X.B. Chen, Ling Qian, Zhihua Ma. Numerical investigation of viscous effects on the gap resonance between side-by-side barges. Ocean Engineering. 2017; 145 ():44-58.

Chicago/Turabian Style

Xingya Feng; W. Bai; X.B. Chen; Ling Qian; Zhihua Ma. 2017. "Numerical investigation of viscous effects on the gap resonance between side-by-side barges." Ocean Engineering 145, no. : 44-58.

Journal article
Published: 01 March 2017 in Coastal Engineering
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ACS Style

Jun Tang; Yongming Shen; Derek M. Causon; Ling Qian; Clive G. Mingham. Numerical study of periodic long wave run-up on a rigid vegetation sloping beach. Coastal Engineering 2017, 121, 158 -166.

AMA Style

Jun Tang, Yongming Shen, Derek M. Causon, Ling Qian, Clive G. Mingham. Numerical study of periodic long wave run-up on a rigid vegetation sloping beach. Coastal Engineering. 2017; 121 ():158-166.

Chicago/Turabian Style

Jun Tang; Yongming Shen; Derek M. Causon; Ling Qian; Clive G. Mingham. 2017. "Numerical study of periodic long wave run-up on a rigid vegetation sloping beach." Coastal Engineering 121, no. : 158-166.

Journal article
Published: 16 July 2016 in Ocean Engineering
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This paper presents a numerical investigation of a plunging wave impact event in a low-filling depressurised sloshing tank using a compressible multiphase flow model implemented in open-source CFD software. The main focus of this study is on the hydrodynamic loadings that impinge on the vertical wall of the tank. The detailed numerical solutions compare well with experimental results and confirm that an air trapped plunging wave impact causes the vertical wall to experience pulsating pressure loadings in which alternate positive and negative gauge pressures occur in sequence following the first applied pressure peak. The strongest pulsations of the pressure are found to be near the air pocket trapped by the water mass. The instantaneous pressure distribution along the vertical wall is nearly uniform in the area contained by the air pocket. The phases of pulsating pressures on the wall are in synchronisation with the expansion and contraction of the trapped air pocket. The pocket undergoes changes in shape, moves upwards with the water mass and eventually breaks up into small parts. A careful integration of the wall pressure reveals that the vertical structure as a whole experiences pulsating horizontal impact forces. It is found that the average period of pulsation cycles predicted in the present study is around 5–6 ms, and the loading pulsations are quickly damped out in 0.1–0.2s. Further exploratory investigation of the fluid thermodynamics reveals that the temperature inside the trapped air pocket rises quickly for about 2 ms synchronised with the pocket's first contraction, then the generated heat is rapidly transferred away in around 3 ms.

ACS Style

Z.H. Ma; D.M. Causon; Ling Qian; C.G. Mingham; Pedro J. Martínez-Ferrer. Numerical investigation of air enclosed wave impacts in a depressurised tank. Ocean Engineering 2016, 123, 15 -27.

AMA Style

Z.H. Ma, D.M. Causon, Ling Qian, C.G. Mingham, Pedro J. Martínez-Ferrer. Numerical investigation of air enclosed wave impacts in a depressurised tank. Ocean Engineering. 2016; 123 ():15-27.

Chicago/Turabian Style

Z.H. Ma; D.M. Causon; Ling Qian; C.G. Mingham; Pedro J. Martínez-Ferrer. 2016. "Numerical investigation of air enclosed wave impacts in a depressurised tank." Ocean Engineering 123, no. : 15-27.

Contributors
Published: 24 June 2016 in Numerical Modelling of Wave Energy Converters
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ACS Style

M. Alves; D. Causon; B. Child; J. Davidson; B. Elsäßer; C.B. Ferreira; C.J. Fitzgerald; M. Folley; D. Forehand; S. Giorgi; J.P. Kofoed; L. Kregting; C. Mingham; L. Qian; P. Ricci; J.V. Ringwood; V. Stratigaki; P. Troch; S. Vaughan. Contributors. Numerical Modelling of Wave Energy Converters 2016, 1 .

AMA Style

M. Alves, D. Causon, B. Child, J. Davidson, B. Elsäßer, C.B. Ferreira, C.J. Fitzgerald, M. Folley, D. Forehand, S. Giorgi, J.P. Kofoed, L. Kregting, C. Mingham, L. Qian, P. Ricci, J.V. Ringwood, V. Stratigaki, P. Troch, S. Vaughan. Contributors. Numerical Modelling of Wave Energy Converters. 2016; ():1.

Chicago/Turabian Style

M. Alves; D. Causon; B. Child; J. Davidson; B. Elsäßer; C.B. Ferreira; C.J. Fitzgerald; M. Folley; D. Forehand; S. Giorgi; J.P. Kofoed; L. Kregting; C. Mingham; L. Qian; P. Ricci; J.V. Ringwood; V. Stratigaki; P. Troch; S. Vaughan. 2016. "Contributors." Numerical Modelling of Wave Energy Converters , no. : 1.

Journal article
Published: 19 March 2016 in Ocean Engineering
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Square and circular cylinders in three-dimensional turbulent flows are studied numerically using the LES and DES turbulence models. One aim of the present study is to implement the LES and DES turbulence models in a cell-centered finite volume method (FVM) developed for solving the Navier–Stokes equations on Cartesian cut cells. The Cartesian cut cell approach is known to be robust for problems in geometrically complex domains with fixed or moving boundaries. For the purpose of validating the present numerical model, the current flow past fixed square and circular cylinders at moderate Reynolds numbers is tested first. Comparison of the computed results with experimental data reveals that the DES models are superior to the conventional LES and RANS models. The second aim of the present study is to assess the performance of different RANS based DES turbulence models. By means of the comparison of results obtained with the 0-equation mixing-length, 1-equation S–A and 2-equation k–ω based DES models for the flow over the same circular cylinder, some recommendations are proposed. According to the present study, in terms of accuracy the 1-equation S–A based DES model is very promising. Beside this, if the computational cost is the main concern, the 0-equation mixing-length based DES model might be an ideal option, achieving a good balance between accuracy and efficiency.

ACS Style

W. Bai; C.G. Mingham; D.M. Causon; L. Qian. Detached eddy simulation of turbulent flow around square and circular cylinders on Cartesian cut cells. Ocean Engineering 2016, 117, 1 -14.

AMA Style

W. Bai, C.G. Mingham, D.M. Causon, L. Qian. Detached eddy simulation of turbulent flow around square and circular cylinders on Cartesian cut cells. Ocean Engineering. 2016; 117 ():1-14.

Chicago/Turabian Style

W. Bai; C.G. Mingham; D.M. Causon; L. Qian. 2016. "Detached eddy simulation of turbulent flow around square and circular cylinders on Cartesian cut cells." Ocean Engineering 117, no. : 1-14.

Journal article
Published: 25 January 2016 in Physics of Fluids
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This paper presents an experimental and numerical investigation of the entry of a rigid square flat plate into pure and aerated water. Attention is focused on the measurement and calculation of the slamming loads on the plate. The experimental study was carried out in the ocean basin at Plymouth University’s COAST laboratory. The present numerical approach extends a two-dimensional hydro-code to compute three-dimensional hydrodynamic impact problems. The impact loads on the structure computed by the numerical model compare well with laboratory measurements. It is revealed that the impact loading consists of distinctive features including (1) shock loading with a high pressure peak, (2) fluid expansion loading associated with very low sub-atmospheric pressure close to the saturated vapour pressure, and (3) less severe secondary reloading with super-atmospheric pressure. It is also disclosed that aeration introduced into water can effectively reduce local pressures and total forces on the flat plate. The peak impact loading on the plate can be reduced by half or even more with 1.6% aeration in water. At the same time, the lifespan of shock loading is prolonged by aeration, and the variation of impulse is less sensitive to the change of aeration than the peak loading.

ACS Style

Z. H. Ma; D. M. Causon; L. Qian; C. G. Mingham; T. Mai; Deborah Greaves; Alison Raby. Pure and aerated water entry of a flat plate. Physics of Fluids 2016, 28, 016104 .

AMA Style

Z. H. Ma, D. M. Causon, L. Qian, C. G. Mingham, T. Mai, Deborah Greaves, Alison Raby. Pure and aerated water entry of a flat plate. Physics of Fluids. 2016; 28 (1):016104.

Chicago/Turabian Style

Z. H. Ma; D. M. Causon; L. Qian; C. G. Mingham; T. Mai; Deborah Greaves; Alison Raby. 2016. "Pure and aerated water entry of a flat plate." Physics of Fluids 28, no. 1: 016104.

Journal article
Published: 02 December 2015 in Computers & Fluids
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We present a multi-region coupling procedure based on the finite-volume method and apply it to two-phase hydrodynamic free surface flow problems. The method combines the features of one incompressible and one compressible two-phase flow solvers to obtain a coupled system which is generally superior to either solver alone. The coupling strategy is based on a partitioned approach in which different solvers, pre-defined in different regions of the computational domain, exchange information through interfaces, i.e. areas separating these regions. The interfaces act as boundary conditions passing the information from one region to the other mimicking the finite-volume cell-to-face interpolation procedures. This results in high performance computing coupled simulations whose functionality can be further extended in order to build a generic numerical wave tank accounting for incompressible flow regions as well as compressibility and aeration effects. We select a series of preliminary benchmarks to verify this coupling procedure which includes the simulation of a hydrodynamic dam break, the propagation and reflection of regular waves, the convection of an inviscid vortex, pseudocavitation, a water column free drop in a closed tank and a plunging wave impact at a vertical wall. The obtained results agree well with exact solutions, laboratory experiments and other numerical data.

ACS Style

P.J. Martínez Ferrer; D.M. Causon; Ling Qian; C.G. Mingham; Zhihua Ma. A multi-region coupling scheme for compressible and incompressible flow solvers for two-phase flow in a numerical wave tank. Computers & Fluids 2015, 125, 116 -129.

AMA Style

P.J. Martínez Ferrer, D.M. Causon, Ling Qian, C.G. Mingham, Zhihua Ma. A multi-region coupling scheme for compressible and incompressible flow solvers for two-phase flow in a numerical wave tank. Computers & Fluids. 2015; 125 ():116-129.

Chicago/Turabian Style

P.J. Martínez Ferrer; D.M. Causon; Ling Qian; C.G. Mingham; Zhihua Ma. 2015. "A multi-region coupling scheme for compressible and incompressible flow solvers for two-phase flow in a numerical wave tank." Computers & Fluids 125, no. : 116-129.

Journal article
Published: 21 July 2015 in Computers & Fluids
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This paper presents a GPU based compressible multiphase hydrocode for modelling violent hydrodynamic impacts under harsh conditions such as slamming and underwater explosion. An effort is made to extend a one-dimensional five-equation reduced model (Kapila et al., 2001) to compute three-dimensional hydrodynamic impact problems on modern graphics hardware. In order to deal with free-surface problems such as water waves, gravitational terms, which are initially absent from the original model, are now considered and included in the governing equations. A third-order finite volume based MUSCL scheme is applied to discretise the integral form of the governing equations. The numerical flux across a mesh cell face is estimated by means of the HLLC approximate Riemann solver. The serial CPU program is firstly parallelised on multi-core CPUs with the OpenMP programming model and then further accelerated on many-core graphics processing units (GPUs) using the CUDA C programming language. To balance memory usage, computing efficiency and accuracy on multi- and many-core processors, a mixture of single and double precision floating-point operations is implemented. The most important data like conservative flow variables are handled with double-precision dynamic arrays, whilst all the other variables/arrays like fluxes, residual and source terms are treated in single precision. Several benchmark test cases including water-air shock tubes, one-dimensional liquid cavitation tube, dam break, 2D cylindrical underwater explosion near a planar rigid wall, 3D spherical explosion in a rigid cylindrical container and water entry of a 3D rigid flat plate have been calculated using the present approach. The obtained results agree well with experiments, exact solutions and other independent numerical computations. This demonstrates the capability of the present approach to deal with not only violent free-surface impact problems but also hull cavitation associated with underwater explosions. Performance analysis reveals that the running time cost of numerical simulations is dramatically reduced by use of GPUs with much less consumption of electrical energy than on the CPU.

ACS Style

Z.H. Ma; D.M. Causon; Ling Qian; H.B. Gu; C.G. Mingham; Pedro J. Martínez-Ferrer. A GPU based compressible multiphase hydrocode for modelling violent hydrodynamic impact problems. Computers & Fluids 2015, 120, 1 -23.

AMA Style

Z.H. Ma, D.M. Causon, Ling Qian, H.B. Gu, C.G. Mingham, Pedro J. Martínez-Ferrer. A GPU based compressible multiphase hydrocode for modelling violent hydrodynamic impact problems. Computers & Fluids. 2015; 120 ():1-23.

Chicago/Turabian Style

Z.H. Ma; D.M. Causon; Ling Qian; H.B. Gu; C.G. Mingham; Pedro J. Martínez-Ferrer. 2015. "A GPU based compressible multiphase hydrocode for modelling violent hydrodynamic impact problems." Computers & Fluids 120, no. : 1-23.

Conference paper
Published: 08 December 2014 in Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences
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This paper focuses on the numerical modelling of wave impact events under air entrapment and aeration effects. The underlying flow model treats the dispersed water wave as a compressible mixture of air and water with homogeneous material properties. The corresponding mathematical equations are based on a multiphase flow model which builds on the conservation laws of mass, momentum and energy as well as the gas-phase volume fraction advection equation. A high-order finite volume scheme based on monotone upstream-centred schemes for conservation law reconstruction is used to discretize the integral form of the governing equations. The numerical flux across a mesh cell face is estimated by means of the HLLC approximate Riemann solver. A third-order total variation diminishing Runge–Kutta scheme is adopted to obtain a time-accurate solution. The present model provides an effective way to deal with the compressibility of air and water–air mixtures. Several test cases have been calculated using the present approach, including a gravity-induced liquid piston, free drop of a water column in a closed tank, water–air shock tubes, slamming of a flat plate into still pure and aerated water and a plunging wave impact at a vertical wall. The obtained results agree well with experiments, exact solutions and other numerical computations. This demonstrates the potential of the current method to tackle more general wave–air–structure interaction problems.

ACS Style

Z. H. Ma; D. M. Causon; Ling Qian; C. G. Mingham; H. B. Gu; Pedro J. Martínez-Ferrer. A compressible multiphase flow model for violent aerated wave impact problems. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 2014, 470, 20140542 .

AMA Style

Z. H. Ma, D. M. Causon, Ling Qian, C. G. Mingham, H. B. Gu, Pedro J. Martínez-Ferrer. A compressible multiphase flow model for violent aerated wave impact problems. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences. 2014; 470 (2172):20140542.

Chicago/Turabian Style

Z. H. Ma; D. M. Causon; Ling Qian; C. G. Mingham; H. B. Gu; Pedro J. Martínez-Ferrer. 2014. "A compressible multiphase flow model for violent aerated wave impact problems." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 470, no. 2172: 20140542.