Nested Streamtube Fluid Manipulation for Low-Speed Thrust Efficiency
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Solution Overview
Problem
Existing fluid interaction apparatuses, such as helicopters and wind turbines, face inefficiencies in power consumption and thrust production at low free stream flow velocities due to high drag forces and limited duct geometry, leading to increased power requirements and reduced performance.
Innovation Solution
A fluid manipulation apparatus is configured to modify the local free stream velocity and reduce viscous drag by using a thrust apparatus assembly with upstream and downstream components that impart and extract momentum, reducing power consumption and enhancing thrust production.
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 due to large diffuser geometry
Solution Approach 1:
The invention divides the fluid interaction system into multiple independent thrust apparatuses (upstream and downstream) rather than using a single complex ducted system. Each apparatus operates independently to modify the streamtube, allowing the system to achieve velocity modification without requiring a large, complex duct structure.
Solution Approach 2:
The downstream thrust apparatus is positioned within the streamtube of the upstream thrust apparatus, creating a nested configuration. This allows the downstream apparatus to interact with the already-modified flow field, achieving cumulative effects on the streamtube without requiring additional external ducting structures.
2Object-affected harmful factors
If the wetted surface is made smooth to reduce viscous drag, then the drag force is reduced, but the device complexity increases due to manufacturing requirements
Solution Approach 1:
Instead of focusing solely on surface smoothness (one-dimensional approach), the invention addresses drag reduction by modifying the three-dimensional flow field structure. By using multiple thrust apparatuses to create a modified streamtube, the system reduces the velocity gradient at the wetted surface from a holistic flow field perspective, rather than relying only on surface geometry.
3Force
If power is increased to maintain thrust at low free stream velocities, then the thrust production is maintained, but the energy consumption increases significantly
Solution Approach 1:
The upstream thrust apparatus performs preliminary action by modifying the streamtube and increasing the local flow velocity before the fluid reaches the downstream apparatus. This pre-conditioning of the flow field allows the downstream apparatus to operate more efficiently, extracting power from the already-accelerated flow, thereby reducing the total power required compared to a single apparatus operating alone at low free stream velocities.
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 by modifying local free stream velocities and reducing drag forces, thereby improving the efficiency of thrust production and power extraction.
Implementation Method 1
an upstream thrust apparatus configured to impart a rate of change of momentum to a fluid element in a first direction
Implementation Method 2
a downstream thrust apparatus configured to impart a rate of change of momentum to the fluid element in a second direction opposite the first direction
Implementation Method 3
The aforementioned viscous drag force is a function of the local free stream velocity of the fluid relative to the wetted surface of the object
Data Source
AI summary
An intentional fluid manipulation apparatus (IFMA) assembly that includes an upstream intentional momentum shedding apparatus (IMSA) configured to impart a first induced velocity to a local free stream flow during a nominal operation requirement. The upstream IMSA creates a streamtube. The IFMA includes a downstream IMSA, with some or all of the downstream IMSA being located in a downstream portion of the streamtube. The downstream IMSA imparts a second induced velocity to the local free stream flow within the streamtube. The second induced velocity at the location of the downstream IMSA has a component in a direction opposite to the direction of the first induced velocity at the location of the downstream IMSA.