A Cartesian grid based multiphase flow model for water impact of an arbitrary complex body
A Cartesian grid based multiphase flow model for water impact of an arbitrary complex body
A Cartesian grid based multiphase flow model is developed to simulate water impact problems. This model is capable of simulating complex moving bodies interacting with a highly non-linear free surface such as jet flow or air cushion. A radial basis function based ghost cell method (RBFGCM) is developed to treat the arbitrary moving body on a fixed Cartesian grid. The complex moving boundary is tracked with the RBF and ghost cells are identified based on the signed function property of the RBF. To capture large deformation of the free surface, a gradient-augmented level set (GALS) method is used. Sub-grid resolution is obtained by simultaneously evolving both the level set (LS) function and its gradient information. Also, a simple distance function assignment method is developed to treat the contact boundary between the free surface and the solid surface. The accuracies of the ghost cell method (GCM) and the GALS method are validated by inline oscillation of a cylinder and horizontal sloshing cases, respectively. Then, the water impact of an arbitrary body is simulated. The cases include the water entry of a free falling multihull and the water entry of a bow-flare ship section with various roll angles. The accuracy of the proposed multiphase flow model and its capability are examined by comparing the present results to experimental and numerical results. Also, the results show that the present method can more accurately predict the slamming load in the presence of flow separation and air cushion than the smoothed particle hydrodynamics (SPH) based single-phase flow model and the boundary element method (BEM). Furthermore, the influence of roll angles on the slamming load and the free surface are studied.
Complex geometry, Ghost cell method, Gradient-augmented level set method, Multiphase flow, Radial basis function, Water impact
132-147
Shi, Fulong
938aceea-880e-499f-8486-3c39892952c1
Xin, Jianjian
a99a1d46-ad71-4efc-a190-c93e7fee0a38
Jin, Qiu
27d56f4b-3b1f-4bd9-aab7-ebd3331912d1
January 2019
Shi, Fulong
938aceea-880e-499f-8486-3c39892952c1
Xin, Jianjian
a99a1d46-ad71-4efc-a190-c93e7fee0a38
Jin, Qiu
27d56f4b-3b1f-4bd9-aab7-ebd3331912d1
Shi, Fulong, Xin, Jianjian and Jin, Qiu
(2019)
A Cartesian grid based multiphase flow model for water impact of an arbitrary complex body.
International Journal of Multiphase Flow, 110, .
(doi:10.1016/j.ijmultiphaseflow.2018.09.008).
Abstract
A Cartesian grid based multiphase flow model is developed to simulate water impact problems. This model is capable of simulating complex moving bodies interacting with a highly non-linear free surface such as jet flow or air cushion. A radial basis function based ghost cell method (RBFGCM) is developed to treat the arbitrary moving body on a fixed Cartesian grid. The complex moving boundary is tracked with the RBF and ghost cells are identified based on the signed function property of the RBF. To capture large deformation of the free surface, a gradient-augmented level set (GALS) method is used. Sub-grid resolution is obtained by simultaneously evolving both the level set (LS) function and its gradient information. Also, a simple distance function assignment method is developed to treat the contact boundary between the free surface and the solid surface. The accuracies of the ghost cell method (GCM) and the GALS method are validated by inline oscillation of a cylinder and horizontal sloshing cases, respectively. Then, the water impact of an arbitrary body is simulated. The cases include the water entry of a free falling multihull and the water entry of a bow-flare ship section with various roll angles. The accuracy of the proposed multiphase flow model and its capability are examined by comparing the present results to experimental and numerical results. Also, the results show that the present method can more accurately predict the slamming load in the presence of flow separation and air cushion than the smoothed particle hydrodynamics (SPH) based single-phase flow model and the boundary element method (BEM). Furthermore, the influence of roll angles on the slamming load and the free surface are studied.
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Accepted/In Press date: 21 September 2018
e-pub ahead of print date: 22 September 2018
Published date: January 2019
Keywords:
Complex geometry, Ghost cell method, Gradient-augmented level set method, Multiphase flow, Radial basis function, Water impact
Identifiers
Local EPrints ID: 427089
URI: http://eprints.soton.ac.uk/id/eprint/427089
ISSN: 0301-9322
PURE UUID: d072936d-cc7d-4235-baa5-38322d2c6323
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Date deposited: 21 Dec 2018 16:31
Last modified: 15 Mar 2024 22:06
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Author:
Fulong Shi
Author:
Jianjian Xin
Author:
Qiu Jin
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