Torpedo Anchor Installation Hydrodynamics

Fernandes, Antonio Carlos; Araujo, Jairo Bastos de; Almeida, Jose ́ Carlos Lima de; Machado, R.D.; Matos, Vinícius L.F.

doi:10.1115/1.2355514

Cited by 38 publications

(15 citation statements)

References 1 publication

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“…This is a result already noticed in Fernandes et al (2006), although not using the present Routh-Hurwitz analysis. In fact, the condition (30) is required for any torpedo pile since then.…”

Section: Routh-hurwitz Analysissupporting

confidence: 76%

“…With Equation (20), the so-called Routh-Hurwitz analysis may be performed (see for instance Fernandes et al (2006)). The necessary and sufficient (NS i ) condition requires that all three Hurwitz determinants (D i ) are positive, that is,…”

Section: Routh-hurwitz Analysismentioning

confidence: 99%

“…This so-called torpedo anchoring was invented and made feasible by Petrobras by organising several full-scale expeditions. However, more specifically, for its installation procedure, a comprehensive model test campaign was performed (Fernandes et al 2006) what helped with preliminary hydrodynamic adjustments. The initial configuration of the installation procedure is shown in Figure 2.…”

Section: Introductionmentioning

confidence: 99%

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Directional stability of the torpedo anchor pile during its installation

Fernandes

Sales

Silva

et al. 2011

The IES Journal Part A: Civil & Structural Engineering

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The so-called torpedo anchoring system is a novel and yet already intensively field-proven by Petrobras (the Brazilian oil company) offshore, Brazil. It is a pile with a specific elongated form that is buried in the sea bottom to hold mooring lines that are connected to floating production units. This is so even for very deep water (typically 1800 m). The methodology of installation of the torpedo pile so far consists of a vertical launching, starting with the torpedo above and close (typically 100 m) to the sea bottom. This installation path then occurs from the pile at the starting position with zero velocity until it reaches the bottom. During this installation, the pile travels almost freely, only dragging the mooring line. It is obvious that the object has to have a minimum directional stability to arrive vertically at the bottom. The pile becomes useless when it gets a vertical angle that is outside certain limits (typically three degrees). The present article addresses the directional stability of the torpedo pile during the installation.

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“…This is a result already noticed in Fernandes et al (2006), although not using the present Routh-Hurwitz analysis. In fact, the condition (30) is required for any torpedo pile since then.…”

Section: Routh-hurwitz Analysissupporting

confidence: 76%

Section: Routh-hurwitz Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Directional stability of the torpedo anchor pile during its installation

Fernandes

Sales

Silva

et al. 2011

The IES Journal Part A: Civil & Structural Engineering

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“…In order to define the impact velocity, two main hydrodynamic aspects should be discussed: the drag problem and directional stability problem (Fernandes, 2006). The impact velocity, in this step, implies the upper and lower boundaries.…”

Section: Impact Velocitymentioning

confidence: 99%

Damage Assessment of Free-fall Dropped Object on Sub-seabed in Offshore Operation

Won

Kim²,

Park

et al. 2015

Journal of Advanced Research in Ocean Engineering

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This paper presents the damage assessment of a free-fall dropped object on the seabed. The damage to a dropped object totally depends on the relationship between the impact energy and the soil strength at the mudline. In this study, unexpected dropping scenarios were first assumed by varying the relevant range of the impact velocity, structure geometry at the moment of impact, and soil strength profile along the penetration depth. Theoretical damage assessments were then undertaken for a free-fall dropping event with a fixed final embedment depth for the structure. This paper also describes the results of a three-dimensional large deformation finite element analysis undertaken for the purpose of validation. The analyses were carried out using the coupled Eulerian-Lagrangian approach, modifying the simple elastic-perfectly plastic Tresca soil model. The validation exercises for each dropping scenario showed good agreement, and the present numerical approach was capable of predicting the behavior of a free-fall dropped object.

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“…Fernandes et al (2006) conducted small scale laboratory tests by using scaled torpedo anchors according to their design ratio. It was determined that presence of rear lines could increase the drag acting against torpedo anchor while it is travelling vertically downward.…”

Section: Introductionmentioning

confidence: 99%

Numerical analyses for improved terminal velocity of deep water torpedo anchor

Soh

Pao

Chen

2017

HFF

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Torpedo anchor is an innovative anchor solution for deep water applications.Typically, the anchor is released from a drop height of greater than 50 meters from seabed, and eventually penetrates into the seabed through free fall. As global offshore oil and gas exploration and production activities are now leaning towards regions with deeper sea death, there is a need for the anchor to achieve higher terminal velocity before impact so as to achieve deeper penetration with greater holding capacity. Literature review showed that there is a lack of research data available for improvement on terminal velocity itself. Furthermore, there is no established guideline for the designs of torpedo anchors. This research aims to investigate the effects of manipulation of torpedo's geometries in order to attain higher terminal velocity. The parameters of interest include geometric changes of the original design, as well as sea water properties that reflect water depth in South China Sea. Besides, new design features are proposed and investigated in the overall parametric studies. It was found that the terminal velocity can be improved by sharper tip angle, greater aspect ratio, greater diameter ratio, and an optimum rear angle at 30 o . Sensitivity of drag coefficient towards each of the parameters is established in this paper.2

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Torpedo Anchor Installation Hydrodynamics

Cited by 38 publications

References 1 publication

Directional stability of the torpedo anchor pile during its installation

Directional stability of the torpedo anchor pile during its installation

Damage Assessment of Free-fall Dropped Object on Sub-seabed in Offshore Operation

Numerical analyses for improved terminal velocity of deep water torpedo anchor

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