Low Drag Mirror Using Passive Jet Flow Control
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Solution Overview
Problem
External side view mirrors on motor vehicles create significant drag and noise due to their shape, leading to increased fuel consumption and noise pollution, particularly in smaller vehicles where drag forces decelerate them more readily.
Innovation Solution
The implementation of low drag low noise devices that use passive jet flow control to manipulate air flow around the mirrors, creating directed jets that counter base flow and reduce vortex shedding, thereby minimizing drag and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external side view mirrors are used on motor vehicles, then visibility and safety are improved, but drag and noise increase significantly
Solution Approach 1:
The mirror assembly is divided into separate functional components: the mirror housing, the jet flow control device with multiple nozzles, and the base mounting structure. This segmentation allows the jet flow control system to be independently optimized to reduce drag and noise without compromising mirror functionality.
Solution Approach 2:
A jet flow control device is introduced as an intermediary system between the mirror housing and the oncoming airflow. This device uses directed jets of air to manipulate the base flow and reduce vortex shedding, thereby decreasing drag and noise while preserving the mirror's visibility function.
2Use of energy by moving object
If smaller and lighter vehicles are used, then fuel efficiency and emissions are improved, but drag forces have a greater decelerating effect
Solution Approach 1:
The jet flow control device changes the flow parameters (velocity, direction, pressure) of the air passing through and around the mirror housing. By actively manipulating these parameters, the system reduces the drag force impact on smaller vehicles, allowing them to maintain better fuel efficiency despite their lower mass.
3Ease of manufacture
If traditional mirror housing shapes are used, then manufacturing is simplified, but vortex shedding creates significant noise and drag
Solution Approach 1:
The jet flow control device incorporates curved surfaces and rounded edges in its design, which helps to smooth airflow transitions and reduce vortex shedding. These curved geometries are integrated into the mirror housing in a way that maintains manufacturability while significantly decreasing noise and drag generation.
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 solution effectively reduces drag and noise by creating a virtual trailing edge, enhancing fuel efficiency and reducing noise pollution, particularly beneficial for smaller vehicles.
Implementation Method 1
The jet flow control devices described herein can be used to reduce the drag and noise on any suitable motor vehicle
Implementation Method 2
Drag and noise are a direct result of the flow conditions created by the shape of the side view mirrors. For example, flow conditions such as high turbulent pressure fluctuations and vortex shedding create drag, noise, and a low base pressure behind the flat rear surface of the mirror
Data Source
AI summary
Low drag low noise devices are described herein that use passive jet flow control to reduce the drag and noise created by motor vehicles (e.g., motor vehicle side view mirrors) while the motor vehicles travel through a fluid. The low drag low noise devices described herein comprise a lengthwise axis, an outer body, and an inner body. The outer body and the inner body cooperatively define a channel through which fluid can pass during use.