Vertical Wind Tunnel Noise Reduction via Flow Straightening
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Solution Overview
Problem
Existing open vertical wind tunnels face challenges in reducing noise levels generated by propellers and air flow while maintaining flight performance and power efficiency, particularly in simulating free fall skydiving conditions.
Innovation Solution
The design incorporates a frame structure with a flow straightening assembly and sound attenuating panels, featuring a vertical cylindrical housing with a central cone and radially oriented guide vanes, along with sound absorption materials and perforated metal plates to absorb and direct noise away from the user, ensuring reduced noise levels without compromising performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If noise reduction measures are implemented in open vertical wind tunnels, then noise levels are reduced, but flight performance and power efficiency may be compromised
Solution Approach 1:
The noise reduction system is segmented into multiple functional components: flow straightening assembly with guide vanes, sound attenuating panels with absorption material, and perforated metal plates. Each component addresses specific aspects of noise reduction while maintaining separate functional integrity, allowing optimization of each element without compromising overall flight performance.
Solution Approach 2:
The perforated metal plates serve as intermediaries between the propeller and the surrounding environment. These plates allow controlled air flow while blocking direct propagation of noise waves, acting as a mediator that maintains aerodynamic performance while reducing noise transmission to the user area.
2Object-affected harmful factors
If flow straightening assembly is added to reduce noise, then noise is attenuated, but device complexity increases
Solution Approach 1:
The flow straightening assembly merges multiple functions into a single integrated structure: the guide vanes simultaneously straighten the airflow pattern and redirect noise waves, while the housing integrates both aerodynamic and acoustic functions. This consolidation reduces overall system complexity compared to separate independent components.
Solution Approach 2:
The guide vanes in the flow straightening assembly perform multiple functions: they straighten turbulent airflow from the propeller, redirect noise waves away from the user area, and maintain structural integrity of the assembly. This multi-functionality reduces the need for additional separate components, thereby limiting complexity increase.
3Object-affected harmful factors
If sound absorption material is installed in frame structure sections, then noise is absorbed, but manufacturing complexity increases
Solution Approach 1:
Sound absorption material is applied locally only in specific frame structure sections where noise propagation is most problematic, rather than uniformly throughout the entire structure. This localized application minimizes manufacturing complexity and material usage while achieving effective noise reduction in critical areas.
Solution Approach 2:
The sound absorption material utilized has porous characteristics that allow it to be installed in standardized sections of the frame structure. The porous nature enables the material to be compressed and fitted into existing structural voids, simplifying installation processes and reducing manufacturing complexity compared to dense or irregularly shaped absorption materials.
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
This configuration effectively reduces noise levels and maintains flight performance by straightening airflow and absorbing noise, creating a more immersive and quieter skydiving simulation experience.
Implementation Method 1
sound absorption material... absorbs noise generated by the power unit and the fan assembly
Implementation Method 2
flow straightening assembly that in addition of straightening an air flow generated by rotation of a propeller about a vertical axis
Implementation Method 3
Said perforated metal plates provide noise reduction in a lower part of the vertical wind tunnel
Data Source
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AI summary
Invention relates to an open vertical wind tunnels for simulating a free fall sky diving. An open vertical wind tunnel comprising: a frame structure (1), a power unit (2) and a fan assembly (3); a flow straightening assembly (4) comprising a vertical cylindrical housing (42) to be mounted above and coaxially with the propeller (3); a central cone (43) disposed within and coaxially with the vertical cylindrical housing (42); a plurality of radially oriented vertically disposed guide vanes (44), where each guide vane (44) is configured to straighten an air flow and absorb created noise; a flight platform (5); and sound attenuating panels (6) arranged around the open vertical wind tunnel.