Vortex generator is basically an aerodynamic design to increase the velocity of the lethargic air flow above an aerofoil shape of a body. Your car especially if you are driving a sedan car which at the back of your car will have a point where the air will separate at higher speed. This creates turbulent and leading to increasing drag on your car. The air flow should be smooth until the end of your car which is at the most rear of your car.
That is why a sedan car will have more effect of drag at high speed compared to hatchback because hatchback car have shorter range between separation point which is located on top of your rear window or glass and the rear end. Before you buy a new vortex generator, you need to know the function first. The main objective of installing the vortex generator is to reduce drag by generate vortex which will energize the air flow at separation point to make it smoother and on the other hand, as a cosmetic device for your car for car “make up“.
WANT TO BUY VORTEX GENERATORS FOR YOUR CAR? WHAT IS IT? HOW IT FUNCTIONS? WHY INSTALL VORTEX GENERATOR?
Vortex generators on aircraft wing surfaces
The vortex generator came from an aircraft technologies. When an aircraft flies at high angles of attack (wing angle related to incoming wind), the airflow over the wing can become detached, or it stops following the shape of the wing. When this happens, the lift produced by the wing will suddenly and rapidly decrease, and the wing is said to be stalled. When the flow separates from the wing, it usually means the air is moving too slowly, or there isn’t enough energy in the flow to keep it moving. Since vortices are energetic, they can be used to put energy back into the flow to keep it moving in the desired direction. This is what vortex generators are designed to do.
Vortex generators are simply small rectangular plates that stick out above the wing surface. They look like tiny little wings jutting up perpendicular to the wing itself. As air moves past them, vortices are created off the tips of the generators just like the trailing vortices mentioned earlier. These vortices interact with the rest of the air moving over the wing to speed it up and help reduce the possibility of separation.
Vortex generators are likely to be found on the external surfaces of vehicles where flow separation is a potential problem because vortex generators delay flow separation. On aircraft they are installed on the leading edge of a wing in order to maintain steady airflow over the control surfaces at the rear of the wing. They are typically rectangular or triangular, tall enough to protrude above the boundary layer, and run in spanwise lines near the thickest part of the wing. They can be seen on the wings and vertical tails of many airliners. Vortex generators are positioned in such a way that they have an angle of attack with respect to the local airflow.
A vortex generator creates a tip vortex which draws energetic, rapidly-moving air from outside the slow-moving boundary layer into contact with the aircraft skin. The boundary layer normally thickens as it moves along the aircraft surface, reducing the effectiveness of trailing-edge control surfaces; vortex generators can be used to remedy this problem, among others, by re-energizing the boundary layer.
One of the main causes of aerodynamic drag for sedan vehicles is the separation of flow near the vehicle’s rear end. To delay flow separation, bump-shaped vortex generators are tested for application to the roof end of a sedan. Commonly used on aircraft to prevent flow separation, vortex generators themselves create drag, but they also reduce drag by preventing flow separation at downstream. The overall effect of vortex generators can be calculated by totaling the positive and negative effects. Since this effect depends on the shape and size of vortex generators, those on the vehicle roof are optimized.
However, the VGs that are installed for generating streamwise vortices bring drag by itself. The actual effectiveness of installing VGs is therefore deduced by subtracting the amount of drag by itself from the amount of drag reduction that is yielded by shifting the separation point downstream. Larger-sized VGs increase both the effect of delaying the flow separation and the drag by itself. The effect of delaying the flow separation point, however, saturates at a certain level, which suggests that there must be an optimum size for VGs.
In conclusion, a vortex generator will be useful for sedan car travelling at higher speed to reduce drag and increase the engine efficiency which in turn will help in reducing fuel consumption at high speed.
BM: Kesan memakai atau memasang vortex generator pada kereta serta bagaimana ia berfungsi.
Ok, so in the end why car manufacturers (like Mitshubishi) keep puting VG’s which aren’t placed with an angle like the ones on the airplanes wings – which are proven to be much more effective?