Recirculating-Water Pushing Device for Vessel Resistance Reduction
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Solution Overview
Problem
Existing water surface vessels face high hull resistance, leading to increased power energy consumption, particularly when traveling in recirculating zones behind the transom.
Innovation Solution
A water surface vessel equipped with a pushing device having a concave or scoop-shaped surface, mounted behind the transom, which deflects forward-moving water to generate a forward-directed force, reducing total hull resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional hull design is used, then the vessel structure is simple, but the hull resistance is high leading to increased power energy consumption
Solution Approach 1:
The hull is segmented by adding a separate pushing device behind the transom, dividing the hull into the main vessel structure and the auxiliary pushing surface. This segmentation allows the pushing device to independently interact with the recirculating water without redesigning the entire hull, thereby reducing energy consumption while maintaining structural simplicity.
Solution Approach 2:
The pushing device acts as an intermediary element between the hull and the recirculating water. It captures the forward-moving water in the recirculation zone and converts it into a useful forward-directed force, mediating the interaction between the hull and the water to reduce resistance and power energy consumption.
2Loss of energy
If a pushing device is added to reduce hull resistance, then power energy consumption decreases, but the device complexity increases
Solution Approach 1:
The pushing device is designed to be dynamically adapted to the recirculating flow conditions. The pushing surface is positioned and shaped to optimally interact with the recirculating water at different speeds, allowing it to effectively reduce hull resistance while maintaining a relatively simple structure that can adapt to varying operational conditions.
Solution Approach 2:
The pushing device exploits changes in flow parameters (velocity, direction) in the recirculation zone behind the transom. By positioning the pushing surface to interact with the forward-moving water in this zone, the device converts kinetic energy from the recirculating flow into useful propulsion, reducing hull resistance without requiring complex active control systems.
3Force
If the pushing surface faces forwards, then it would push water backwards to propel the vessel, but it would face into the oncoming water freestream increasing resistance
Solution Approach 1:
Instead of facing the pushing surface directly forwards into the water freestream, the device utilizes the third dimension (vertical placement behind the transom) to access the recirculating water. The pushing surface is positioned in the recirculation zone where water is moving forwards, allowing it to capture this flow without facing the main oncoming water freestream, thus generating propulsion force while avoiding additional resistance.
Solution Approach 2:
The recirculating water behind the transom, which is typically considered wasted energy or a harmful flow pattern, is converted into a beneficial resource. The pushing device captures the forward-moving water in the recirculation zone and redirects it to produce a forward-directed force, transforming what would be energy loss into useful propulsion while avoiding the resistance that would result from facing the main water freestream.
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 pushing device significantly reduces hull resistance by up to 13%, enhancing propulsion efficiency and reducing power consumption.
Implementation Method 1
the pushing surface presents a curvature with at least one center of curvature located on a side of the pushing surface which is opposite to the transom... the pushing surface is concave... the pushing surface may be scoop shaped
Implementation Method 2
the forward moving water in the recirculation zone will act on the pushing surface so as to provide a forwardly directed force transferred from the pushing device to the rest of the vessel
Data Source
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AI summary
The invention relates to a water surface vessel extending in a longitudinal direction parallel to an intended direction of straight travel, the vessel presenting a transom (301), wherein the vessel is arranged to travel in a recirculating zone speed interval in which water is moving towards the transom (301) in a recirculating zone (RZ) behind the transom (301), wherein the vessel comprises a pushing device (311) presenting a pushing surface (312) located in relation to the intended direction of straight travel of the vessel behind the transom (301), at least at portion of the pushing surface (312) facing at least partly backwards in relation to the intended direction of straight travel of the vessel, which pushing surface (312) is arranged to be at least partly submerged into the recirculating zone (RZ) when the vessel is travelling in the recirculation zone speed interval.