The so-called torpedo anchoring system is a novel and yet already intensively field-proven by Pet... more 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.
The installation procedure of a torpedo anchor is the release of the torpedo from a high enough p... more The installation procedure of a torpedo anchor is the release of the torpedo from a high enough position from the sea bottom to allow the device to reach the terminal velocity. A sufficient kinetic energy at the bottom is essential for the penetration. Besides this, the anchor has to reach the bottom in an up right position to maximize the final holding power in all directions. The present work addresses two hydrodynamic aspects for the installation design and analysis. The first is the drag evaluation and the second is the directional stability. If the drag is to be kept small, then the terminal velocity should be high. The work shows that parameters like the mass and the shape are essential for this. On the other hand, the shape and mass distribution have a strong influence on the directional stability. One important parameter is the rear line length connected to the anchor. This line is necessary for further connection with the final mooring line and influences both the terminal velocity and the directional stability. The work addresses all these aspects under the light of a innovative model test setup to be performed in a deep ocean basin. This kind of model testing has been conceived specifically to attend the torpedo anchor evaluation.
Introduction: Myelomeningocele (MMC) is the most frequent of the Neural Tube Defects, with 85% of... more Introduction: Myelomeningocele (MMC) is the most frequent of the Neural Tube Defects, with 85% of the cases. The etiology is unknown, but it has genetic and environmental characteristics. The diagnosis can be achieved in the prenatal period through the morphological ultrasonography. The closing of the defect within the first hours after birth is recommended as well as the early control
In this article we give a simple proof of the existence of kite central configurations in the pla... more In this article we give a simple proof of the existence of kite central configurations in the planar four-body problem which lie on a common circle. We also give a simple proof of the existence of kite central configurations in the spatial five-body problem which lie on a common sphere.
The so-called torpedo anchoring system is a novel and yet already intensively field-proven by Pet... more 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.
The installation procedure of a torpedo anchor is the release of the torpedo from a high enough p... more The installation procedure of a torpedo anchor is the release of the torpedo from a high enough position from the sea bottom to allow the device to reach the terminal velocity. A sufficient kinetic energy at the bottom is essential for the penetration. Besides this, the anchor has to reach the bottom in an up right position to maximize the final holding power in all directions. The present work addresses two hydrodynamic aspects for the installation design and analysis. The first is the drag evaluation and the second is the directional stability. If the drag is to be kept small, then the terminal velocity should be high. The work shows that parameters like the mass and the shape are essential for this. On the other hand, the shape and mass distribution have a strong influence on the directional stability. One important parameter is the rear line length connected to the anchor. This line is necessary for further connection with the final mooring line and influences both the terminal velocity and the directional stability. The work addresses all these aspects under the light of a innovative model test setup to be performed in a deep ocean basin. This kind of model testing has been conceived specifically to attend the torpedo anchor evaluation.
Introduction: Myelomeningocele (MMC) is the most frequent of the Neural Tube Defects, with 85% of... more Introduction: Myelomeningocele (MMC) is the most frequent of the Neural Tube Defects, with 85% of the cases. The etiology is unknown, but it has genetic and environmental characteristics. The diagnosis can be achieved in the prenatal period through the morphological ultrasonography. The closing of the defect within the first hours after birth is recommended as well as the early control
In this article we give a simple proof of the existence of kite central configurations in the pla... more In this article we give a simple proof of the existence of kite central configurations in the planar four-body problem which lie on a common circle. We also give a simple proof of the existence of kite central configurations in the spatial five-body problem which lie on a common sphere.
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Papers by Antonio Carlos Fernandes
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.
The present work addresses two hydrodynamic aspects for the installation design and analysis. The first is the drag evaluation and the second is the directional stability. If the drag is to be kept small, then the terminal velocity should be high. The work shows that parameters like the mass and the shape are essential for this. On the other hand, the shape and mass distribution have a strong influence on the directional stability. One important parameter is the rear line length connected to the anchor. This line is necessary for further connection with the final mooring line and influences both the terminal velocity and the directional stability.
The work addresses all these aspects under the light of a innovative model test setup to be performed in a deep ocean basin. This kind of model testing has been conceived specifically to attend the torpedo anchor evaluation.
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.
The present work addresses two hydrodynamic aspects for the installation design and analysis. The first is the drag evaluation and the second is the directional stability. If the drag is to be kept small, then the terminal velocity should be high. The work shows that parameters like the mass and the shape are essential for this. On the other hand, the shape and mass distribution have a strong influence on the directional stability. One important parameter is the rear line length connected to the anchor. This line is necessary for further connection with the final mooring line and influences both the terminal velocity and the directional stability.
The work addresses all these aspects under the light of a innovative model test setup to be performed in a deep ocean basin. This kind of model testing has been conceived specifically to attend the torpedo anchor evaluation.