Submerged Periodic Riblets for Low-Drag Surface Flow
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Solution Overview
Problem
Conventional riblets that protrude above the surface of objects increase wetted area, leading to higher pressure drag and reduced drag reduction efficiency, while smooth surfaces do not effectively mitigate drag forces, resulting in increased energy consumption and reduced range for objects moving through fluids.
Innovation Solution
The implementation of submerged periodic riblets, which are depressed below the surface of an object, creating an intermittent pattern that reduces pressure drag and friction drag by damping turbulent structures beyond the riblet section, thereby reducing overall drag without increasing the wetted area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If submerged riblets are used to reduce overall drag, then total drag is reduced, but manufacturing complexity increases
Solution Approach 1:
The submerged riblet structures are incorporated into the surface during the initial manufacturing process rather than being added as a separate post-processing step. This preliminary action integrates the riblet formation with the base surface creation, reducing overall manufacturing complexity.
Solution Approach 2:
The riblet structure is merged with the base surface in a single integrated component. The riblets are formed as part of the surface geometry itself rather than being separate attachments, which simplifies manufacturing by eliminating additional assembly steps and reducing part count.
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
Submerged periodic riblets effectively reduce total drag, including pressure and viscous drag, leading to lower fuel consumption, increased range, and improved propulsion system performance for objects moving through fluids, while maintaining or reducing heat transfer and preventing flow separation.
Implementation Method 1
creating an intermittent pattern that reduces pressure drag and friction drag by damping turbulent structures beyond the riblet section
Implementation Method 2
The use of submerged periodic riblets may delay or prevent the separation of the flow in a turbulent boundary layer from the surface
Data Source
AI summary
In one embodiment, a method for reducing drag includes forming a smooth surface on a first portion of a physical object. The method also includes forming periodic riblets on a second portion of the physical object. The second portion of the physical object is adjacent to the first portion of the physical object. Each riblet of the periodic riblets of the second portion of the physical object is depressed below a plane of the smooth surface of the first portion of the physical object. The method further includes generating a flow over the periodic riblets of the second portion of the physical object and over the smooth surface of the first portion of the physical object. A length of each riblet of the periodic riblets runs parallel to a direction of the flow.