Coanda Thrust Surface with Double Convex Curvature
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Solution Overview
Problem
Existing designs for fluid-flow-based thrust generation, such as flying machines and hovercraft, fail to optimize lift by not considering the precise curvature of surfaces with double convex curvature, leading to inefficiencies in surface area and drag.
Innovation Solution
A thrust generating arrangement utilizing the Coanda effect with a dome-shaped surface of progressive decreasing curvature, maintaining the jet in a bistable state to minimize surface area and drag, featuring a straight downstream periphery and potentially segmented for lightweight construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional surfaces with single-plane curvature are used, then the design is simple and easy to manufacture, but the lift generation efficiency is reduced and drag is increased
Solution Approach 1:
The patent applies double convex curvature to the surface instead of conventional single-plane curvature. This curved surface configuration maintains the jet flow attached to the surface over a longer distance, improving lift generation efficiency while reducing drag, directly resolving the contradiction between manufacturing simplicity and energy loss.
Solution Approach 2:
The patent changes the curvature parameters of the surface by introducing double convex curvature with specific radius of curvature relationships. This parameter modification optimizes the Coanda effect performance, allowing the jet to follow the surface contour more effectively and reduce energy loss from flow separation.
2Loss of energy
If the surface area over which the jet flows is reduced, then drag is minimized, but the curvature precision requirements increase
Solution Approach 1:
By using a dome-shaped surface with double convex curvature, the patent reduces the surface area over which the jet must flow while maintaining effective Coanda effect operation. The specific curvature design allows the jet to remain attached longer, minimizing drag without requiring excessive manufacturing precision.
Solution Approach 2:
The patent applies different curvature characteristics to different regions of the surface. The double convex curvature is strategically designed to optimize jet attachment at critical locations, allowing reduced surface area while maintaining sufficient curvature precision where it matters most for jet flow control.
3Force
If the jet is constrained to follow a curved surface, then lift is improved, but the surface area increases
Solution Approach 1:
The dome-shaped surface with double convex curvature allows the jet to follow the surface contour over an optimized path that generates sufficient lift while minimizing the total surface area involved. The curvature is designed to maintain jet attachment without requiring excessive surface area.
Solution Approach 2:
The patent transitions from conventional two-dimensional curved surfaces to three-dimensional double convex curvature. This dimensional change allows the jet to be constrained more effectively along the surface contour, improving lift generation efficiency while reducing the apparent surface area footprint.
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 solution achieves efficient thrust with reduced drag and enhanced stability and maneuverability by maximizing the Coanda effect over the surface, applicable beyond aircraft to submarines and other fluid-moving vehicles or devices.
Implementation Method 1
a thrust generating arrangement comprising means for causing fluid to flow radially outwardly from a central position over a surface with double convex curvature about an axis, this surface serving to divert the radial flow towards an axial direction by operation of the Coanda effect
Data Source
AI summary
There have been past proposals for air vehicles employing the Coanda effect. In these proposals, a jet of fluid, usually air, is made to flow radially outwardly over 5 a dome-shaped canopy to create lift. A cross-section through the canopy is curved to follow a segment of a circle or it may have a radius of curvature that increases in the direction of flow. In the invention, the radius (r) of the canopy curve decreases towards the downstream direction (x) in a way that is related to the decrease in the width of 10 the jet as it flows over the surface. This means that the radius of curvature decreases (instead of increasing) towards the downstream direction with the rate of decrease being progressively less rapid towards the downstream direction.