## Abstract

This paper presents analysis of steady flow passing through

a porous body in 3D, representing a steady current passing

through a space-frame offshore structure such as an offshore

jacket or a compliant tower. A porous body is used as a proxy

for a space-frame structure to model the effect of current blockage,

which may be interpreted as a global flow and force reduction

relative to the standard Morison drag formulation due

to the presence of the structure as a distributed obstacle. Both

uniform and sheared approach flows are simulated with CFD in

OpenFOAM for a porous body with uniformly distributed resistance.

The behaviour of the blockage due to both types of flow

are compared and contrasted using flow visualisation to illustrate

the interaction of the flow with the body and the evolution

of the resultant wake downstream of the body. The numerical

results are compared with the actuator disc model for uniform

flow due to [8] and the actuator disc model for sheared flow due

to [1]. A porous body with non-uniform vertically distributed

resistance is also considered, and the difference in the flow interaction

relative to body with uniform resistance is analysed

and discussed. The analysis provides the framework for applications

for wind loading on offshore structures such as a spaceframe

during load-out and transportation on a barge, as well as

numerical comparisons for an extension of the [1] model to an

actuator disc with non-uniform resistance.

a porous body in 3D, representing a steady current passing

through a space-frame offshore structure such as an offshore

jacket or a compliant tower. A porous body is used as a proxy

for a space-frame structure to model the effect of current blockage,

which may be interpreted as a global flow and force reduction

relative to the standard Morison drag formulation due

to the presence of the structure as a distributed obstacle. Both

uniform and sheared approach flows are simulated with CFD in

OpenFOAM for a porous body with uniformly distributed resistance.

The behaviour of the blockage due to both types of flow

are compared and contrasted using flow visualisation to illustrate

the interaction of the flow with the body and the evolution

of the resultant wake downstream of the body. The numerical

results are compared with the actuator disc model for uniform

flow due to [8] and the actuator disc model for sheared flow due

to [1]. A porous body with non-uniform vertically distributed

resistance is also considered, and the difference in the flow interaction

relative to body with uniform resistance is analysed

and discussed. The analysis provides the framework for applications

for wind loading on offshore structures such as a spaceframe

during load-out and transportation on a barge, as well as

numerical comparisons for an extension of the [1] model to an

actuator disc with non-uniform resistance.

Original language | English |
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Title of host publication | Proceedings of the 20th Australasian Fluid Mechanics Conference |

Editors | Greg Ivey, Nicole Jones, Tongming Zhou |

Publisher | Australasian Fluid Mechanics Society |

Number of pages | 4 |

ISBN (Electronic) | 9781740523776 |

ISBN (Print) | 978-1-74052-377-6 |

Publication status | Published - 2016 |

Event | Australasian Fluid Mechanics Conference - , Australia Duration: 1 Jan 2011 → … |

### Publication series

Name | Proceedings of the 20th Australasian Fluid Mechanics Conference, AFMC 2016 |
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### Conference

Conference | Australasian Fluid Mechanics Conference |
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Country/Territory | Australia |

Period | 1/01/11 → … |