Dual Thrust Streamtube Assembly for Low-Speed Drag Reduction
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Solution Overview
Problem
Existing fluid interaction apparatuses, such as helicopters and wind turbines, experience inefficiencies in power consumption and thrust production at low free stream flow velocities due to high viscous drag forces and limited effectiveness of conventional methods to mitigate these inefficiencies.
Innovation Solution
A fluid manipulation apparatus is configured to modify the local free stream velocity and reduce viscous drag forces by using a thrust apparatus assembly with upstream and downstream thrust apparatuses that work together to manage momentum and power exchange, reducing power consumption and increasing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a duct is employed to increase the local free stream flow velocity, then the thrust production efficiency is improved, but the device complexity and weight increase prohibitively
Solution Approach 1:
The invention divides the flow manipulation function into multiple discrete elements (streamwise-aligned structures) distributed across the wetted surface, rather than using a single large duct. This segmentation allows localized flow modification without the complexity of a comprehensive duct system.
Solution Approach 2:
The invention introduces intermediate flow control elements that act as mediators between the free stream flow and the wetted surface. These elements modify the local flow velocity and direction to reduce viscous drag without requiring a large duct structure.
2Speed
If a large diffuser duct is used to achieve large effect on local free stream flow, then the flow velocity increase is improved, but the wetted area and weight become prohibitively large
Solution Approach 1:
The invention applies flow modification locally at specific regions of the wetted surface where viscous drag is most significant, rather than attempting to modify the entire flow field. This localized approach achieves meaningful drag reduction without requiring a large diffuser duct that would increase wetted area.
Solution Approach 2:
The invention applies partial action by using multiple small flow control elements distributed across the surface, each contributing a small amount of flow modification. Collectively, these elements achieve significant drag reduction without the excessive wetted area of a large duct.
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 apparatus reduces power consumption and increases hovering endurance and thrust production efficiency by managing momentum and power exchange between upstream and downstream thrust apparatuses, minimizing undesired momentum changes and drag forces.
Implementation Method 1
an upstream thrust apparatus configured to impart momentum to a fluid
Implementation Method 2
a downstream thrust apparatus located in a downstream portion of the streamtube... configured to extract power from the fluid
Implementation Method 3
reduce viscous drag forces by using a thrust apparatus assembly with upstream and downstream thrust apparatuses
Data Source
AI summary
An intentional fluid manipulation apparatus (IFMA) assembly with a first thrust apparatus that imparts a first induced velocity to a local free stream flow during a nominal operation requirement. The first thrust apparatus creates a streamtube. A second thrust apparatus is located in a downstream portion of the streamtube. The second thrust apparatus imparts a second induced velocity to the local free stream flow. The second induced velocity at the location of the second thrust apparatus has a component in a direction opposite to the direction of the first induced velocity at the location of the second thrust apparatus.