Plasma Enhanced Riblets for Viscous Drag Reduction
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Solution Overview
Problem
Existing methods for reducing viscous drag on objects moving through fluids, particularly those with turbulent boundary layers, are ineffective in significantly minimizing skin friction, as conventional riblets only achieve a 6% drag reduction despite increasing surface area by 40% and do not effectively manage turbulent mixing vortices.
Innovation Solution
Generating plasma between and above physical riblets or creating virtual riblets using plasma flow to push turbulent mixing vortices away from the surface, utilizing a dielectric barrier discharge device with electrodes to produce plasma jets that are perpendicular to the surface, thereby reducing contact between vortices and the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional riblets are used to reduce viscous drag, then the drag reduction is limited to 6%, but the surface area increases by 40%
Solution Approach 1:
The patent replaces the mechanical riblet structure with a plasma-based system. Instead of using physical grooves to interact with vortices, the invention uses plasma generated by dielectric barrier discharge to actively manage and suppress turbulent mixing vortices, thereby reducing viscous drag without adding surface area
Solution Approach 2:
The invention changes the state of the fluid near the surface by introducing plasma. The plasma modifies local flow parameters such as viscosity and density, creating a virtual riblet effect that reduces drag without the geometric constraints of physical riblets
2Force
If physical riblets are used to manage turbulent mixing vortices, then the vortices are forced away from most surface area, but high viscous drag remains near the riblet peaks
Solution Approach 1:
The patent replaces the mechanical riblet structure with a plasma-based system. Instead of using physical grooves to interact with vortices, the invention uses plasma generated by dielectric barrier discharge to actively manage and suppress turbulent mixing vortices, thereby reducing viscous drag without adding surface area
Solution Approach 2:
The plasma is generated locally at specific positions on the surface using dielectric barrier discharge electrodes. This creates localized regions of modified flow properties that selectively interact with vortices, allowing different areas to have different flow management characteristics without changing the overall surface geometry
3Force
If dielectric barrier discharge device is used to generate plasma jets, then turbulent mixing vortices are pushed away from the surface, but the device complexity increases
Solution Approach 1:
The dielectric barrier discharge device utilizes the ambient electric field and gas composition to generate plasma. The system is self-regulating, where the plasma generation automatically adjusts to flow conditions, reducing the need for complex control mechanisms while maintaining effective vortex suppression
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 plasma-enhanced riblets and virtual riblets effectively reduce viscous drag associated with turbulent boundary layers without increasing surface area, achieving a more substantial drag reduction than conventional riblets by preventing vortices from contacting the surface, thus improving fluid flow efficiency.
Implementation Method 1
Generating plasma between and above physical riblets or creating virtual riblets using plasma flow
Implementation Method 2
utilizing a dielectric barrier discharge device with electrodes to produce plasma jets
Data Source
AI summary
An object moving through a fluid uses plasma to keep turbulent mixing vortices associated with turbulent air away from the majority of the surface of the object. The plasma may be used to enhance physical riblets, or the plasma may create a virtual riblet.