Vessel Moon Pool With Underwater Cavity for Sloshing Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vessels with moon pools experience significant flow resistance, sloshing, and vortex-induced vibrations due to water motion, which affect sailing performance and increase fuel consumption, and existing solutions either complicate operations or are prone to damage.
Innovation Solution
A vessel design featuring an underwater cavity in front of the moon pool and a second cavity at the rear, both partially open to allow water flow, guiding it away from the moon pool to reduce sloshing and turbulence, with sharp transitions to enhance flow separation and minimize oscillatory behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a moon pool is provided in the hull to allow equipment access to water, then equipment can be lowered and raised into the water, but moon pool sloshing occurs which increases flow resistance and fuel consumption
Solution Approach 1:
A flow control device is introduced as an intermediary element in the moon pool to manage water flow. This device mediates between the need for equipment access and the harmful sloshing effects, allowing operational functionality while controlling the water flow to reduce resistance and energy consumption.
2Use of energy by moving object
If a vortex suppression block is placed in the moon pool to reduce sloshing, then flow resistance decreases, but the front part of the moon pool cannot be used to lower or raise equipment
Solution Approach 1:
The flow control device is designed to be movable rather than fixed, allowing it to change position based on operational needs. During sailing, it assumes a position to suppress sloshing and reduce flow resistance, while during equipment operations, it can be moved aside to clear the moon pool front area for equipment access.
3Stability of the object's composition
If a second vertical passage is added at the rear side of the moon pool to reduce sloshing, then sloshing amplitude decreases, but the deck is penetrated for a relatively large extent
Solution Approach 1:
The flow control function is segmented into separate controllable elements within the moon pool, rather than requiring a large structural modification like a second vertical passage. This allows sloshing control to be achieved through distributed flow management elements that do not require extensive deck penetration.
4Stability of the object's composition
If partition walls or base plates are provided in the moon pool to reduce sloshing, then sloshing is reduced, but these elements placed below the water line can be damaged by equipment or damage equipment
Solution Approach 1:
The flow control device is designed to be dynamically positionable, allowing it to be moved out of the equipment path during operations. This eliminates the collision risk between fixed partition elements and equipment, while maintaining sloshing control functionality when positioned appropriately in the water flow path.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design significantly reduces moon pool sloshing and flow resistance, improving sailing performance and reducing fuel consumption while maintaining a simple, sturdy, and cost-effective structure.
Implementation Method 1
A vessel design featuring an underwater cavity in front of the moon pool and a second cavity at the rear, both partially open to allow water flow, guiding it away from the moon pool to reduce sloshing and turbulence, with sharp transitions to enhance flow separation and minimize oscillatory behavior.
Data Source
Figure 1a~1b
Figure 2a~2c
Figure 3a~3b
AI summary
The invention relates to a vessel (1 ), especially a drillship or so-called drilling ship. The vessel comprises a hull (3) having a bottom surface (5) and a deck (7). Said vessel is provided with a moon pool (2), which extends from said bottom surface of the hull in an upward direction through the hull. Further, said vessel is provided with a cavity (10) located at a front side of the moon pool. Said cavity is at least partly open at a bottom side thereof in order to allow water to flow into said cavity. Moreover, said cavity is at least partly open at a rear side of said cavity in order to allow water to flow directly from said cavity into the moon pool, as a result of which moon pool sloshing can be diminished and the mean flow resistance of the vessel when sailing can be reduced.