Cascading Airfoil Paddle Blade for Low-Vortex Propulsion
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Solution Overview
Problem
Existing paddles that increase drag to propel a watercraft often generate inefficient fluid disturbance and vortex shedding, counteracting the propulsion effect.
Innovation Solution
A paddle design featuring a plurality of overlapping, cascading airfoil-shaped blades that redirect fluid flow along arcuate paths, preventing vortex shedding and increasing drag without linear flow passage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the paddle uses a flat plate normal to fluid flow to increase drag, then propulsion force is improved, but vortex shedding and fluid disturbance increase counteracting the propulsion
Solution Approach 1:
The paddle blade is segmented into multiple parallel airfoil-shaped blades instead of using a single flat plate. This segmentation allows fluid to pass through the gaps between blades while each blade generates lift-oriented drag, reducing vortex shedding and fluid disturbance compared to a solid flat plate configuration
Solution Approach 2:
The blades are designed with airfoil cross-sections featuring curved surfaces rather than flat plates. The airfoil shape with rounded leading edges and cambered surfaces guides fluid flow smoothly along arcuate paths, preventing flow separation and vortex formation while maintaining drag generation for propulsion
2Productivity
If the paddle increases drag to propel watercraft, then propulsion efficiency is improved, but fluid disturbance and vortex shedding increase creating counteracting flow
Solution Approach 1:
The paddle blade is segmented into multiple parallel airfoil-shaped blades instead of using a single flat plate. This segmentation allows fluid to pass through the gaps between blades while each blade generates lift-oriented drag, reducing vortex shedding and fluid disturbance compared to a solid flat plate configuration
Solution Approach 2:
The invention changes the geometric parameters of the paddle blades by using airfoil cross-sections with specific camber and thickness ratios. These parameter changes optimize the balance between drag generation for propulsion and minimization of vortex shedding, improving overall propulsion efficiency while reducing energy loss
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 paddle design achieves increased drag with reduced vortex shedding, enhancing propulsion efficiency by maintaining fluid attachment along the blades and reversing flow direction to align with paddle movement.
Implementation Method 1
Each of the blades may have an airfoil shape
Implementation Method 2
A paddle with a cascading airfoil design produces more drag for the same paddle width and fluid velocity
Implementation Method 3
maintaining fluid flow attachment from the leading to the trailing edge of the blades
Data Source
AI summary
A paddle blade including a plurality of blades that allows fluid flow in between and along the plurality of blades. Each of the plurality of blades may have an airfoil shape and may be positioned parallel to each other. The plurality of blades may include a central diverter blade including two symmetrical, concave lateral faces. The concave lateral faces are configured to redirect, along arcuate paths, fluid flow from a direction approximately perpendicular to a front face of the paddle blade toward lateral sides of the paddle blade. The plurality of blades also includes a first and a second pair of blades positioned on opposite lateral sides of the central diverter blade, each arranged to at least partially overlap either one of the concave lateral faces of the central diverter blade or an adjacent blade of the first pair of blades respectively.