Vehicle Air Deflector Leading Edge Noise Reduction
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Solution Overview
Problem
Conventional wind deflectors for motor vehicles often experience leading edge noise issues such as howling and whistling due to pressure differences causing fluctuating flows at the profile's tip, which conventional designs fail to adequately address.
Innovation Solution
A rough material surface, such as a fabric or fibrous strip, is integrated into the edge region adjoining the front edge of the wind deflector, increasing flow resistance and minimizing noise by reducing compensating currents and pressure fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a smooth profile surface is used for the wind deflector, then the manufacturing is easier and the structure is simpler, but leading edge noise such as howling and whistling occurs due to pressure differences causing fluctuating flows
Solution Approach 1:
The invention applies a rough material surface specifically in the edge region adjoining the front edge, while the rest of the profile maintains its original smooth surface. This localized application of roughness targets the specific area where leading edge noise originates, without requiring the entire profile to be manufactured with rough surface characteristics, thus balancing manufacturing ease with noise reduction.
Solution Approach 2:
The rough material surface functions similarly to porous materials by creating flow resistance through its textured structure. This increases turbulence in the boundary layer at the critical edge region, preventing the formation of coherent vortices that cause howling and whistling noises, while the material itself can be a fabric or fibrous strip that provides this porous-like effect.
2Object-generated harmful factors
If a rough material surface is added to the profile edge region, then leading edge noise is reduced, but the device complexity increases
Solution Approach 1:
The rough material surface is applied only in the specific edge region where noise problems occur, rather than covering the entire profile. This localized approach minimizes the added complexity while maximizing the noise reduction benefit at the critical location.
Solution Approach 2:
The invention combines the base profile material with a rough material surface layer, creating a composite structure. The rough material surface can be a fabric or fibrous strip that is attached to or integrated with the profile, combining the structural function of the profile with the noise-reducing properties of the rough surface material.
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 implementation of a rough material surface effectively reduces excessive leading edge noise, achieving a more advantageous noise behavior by minimizing howling and whistling sounds.
Implementation Method 1
The rough fabric surface increases the flow resistance of the profile without compressive forces being able to settle on the surface
Data Source
Figure 1
AI summary
The invention relates to an air deflection device for a motor vehicle, comprising at least one inherently stiff profiled element (12) around which air flows in at least one position of the profiled element (12) when the motor vehicle drives forward and which has at least one leading edge (14) via which the air flows against the profiled element; a fabric surface (20) is disposed in at least one edge region (18) of the profiled element (12) adjoining the leading edge (14) rearwards in the longitudinal direction of the vehicle.