Tractor Trailer Gap Flow Guide with Vortex Generators
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Solution Overview
Problem
The gap between a truck tractor and a trailer creates aerodynamic drag due to turbulence caused by high pressure air being drawn into the lower pressure gap, despite existing solutions like fairings and flow guides that fail to effectively equalize pressure and reduce turbulence.
Innovation Solution
A flow guiding device is mounted on the truck tractor to divide the air flow boundary layer, directing a higher pressure stream into the gap and rejoining the flow to equalize pressure, reducing turbulence and promoting a lower drag flow to the trailer, with adjustable orientations and vortex generators to optimize airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a fairing is used to close the gap between tractor and trailer, then aerodynamic drag is reduced, but high pressure air is drawn into the low pressure gap creating turbulence and increased drag
Solution Approach 1:
The fairing is divided into multiple sections: a front section that directs flow, a gap section, and a rear section with vortex generators. This segmentation allows each part to perform a specific function in managing airflow and reducing turbulence.
Solution Approach 2:
Vortex generators are introduced as intermediary elements at the rear of the fairing. These generators create controlled vortices that mix the high pressure air from the fairing with the low pressure air in the gap, acting as a mediator to equalize pressures and reduce turbulence.
2Adaptability or versatility
If the gap is left open to allow articulated movements, then steering and road clearance are accommodated, but aerodynamic drag increases due to turbulence
Solution Approach 1:
The fairing provides local coverage only where needed to manage airflow, rather than completely closing the gap. The vortex generators are strategically placed at specific locations to address turbulence only in the critical rear region, allowing the gap to remain open for articulation while managing aerodynamic effects locally.
3Loss of energy
If flow guides are used to direct air flow around the gap, then drag is reduced, but pressure equalization is insufficient leading to continued turbulence
Solution Approach 1:
Vortex generators serve as intermediary devices that actively promote pressure equalization between the high pressure fairing region and the low pressure gap region. The generated vortices create mixing and momentum transfer that stabilizes pressure distribution more effectively than passive flow guides.
Solution Approach 2:
The vortex generators change the flow parameters by creating rotational motion and enhancing mixing between air streams. This alters the pressure distribution parameters and stabilizes the flow composition in the gap region.
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 turbulence and aerodynamic drag by equalizing pressure across the gap, improving airflow and reducing drag on the trailer, while allowing for self-adjustment and dynamic optimization based on airflow conditions.
Implementation Method 1
The invention concerns a flow guiding device placed where a cab side fairing is conventionally positioned on the truck tractor, the flow guiding device shaped to divide an air flow over the truck tractor at a boundary layer
Implementation Method 2
directing a relatively higher pressure stream into the gap side of the device, which causes the pressure at the trailing end of the device to equalize when the flows rejoin
Implementation Method 3
The divided portion rejoins the main portion of the air flow in such a way that turbulence in the air gap is prevented or reduced
Implementation Method 4
An air guiding device according to the invention has two opposing surfaces shaped so that flow on one surface is slower than flow on the other surface. The device may be shaped as an airfoil, having a concave surface and an opposite convex surface.
Data Source
AI summary
An apparatus for affecting airflow in a gap between a lead vehicle and a connected trailing vehicle, includes a guide vane having a leading edge, a trailing edge, a gap side surface, and an outward facing surface, and a support apparatus mountable on a vehicle for supporting the guide vane in a vertical orientation relative to the vehicle with a space between the vehicle and the guide vane gap side surface and with at least a portion of the vane extending beyond an end of the vehicle. The flow guide divides an air flow at the trailing edge of a vehicle to avoid the creation of turbulence in the air flow as it encounters the gap between the vehicle and the trailing vehicle.