REDUCTION OF AERODYNAMIC DRAG BY VORTEX GENERATORS

ByAbhijith C

S7,Mechatronics

WHAT IS AERODYNAMICS???• Aerodynamics is a branch of fluid

dynamics concerned with studying the motion of air, particularly when it interacts with a solid object, such as an airplane wing. 

AUTOMOTIVE AERODYNAMICS

• Automotive aerodynamics is the study of the aerodynamics of road vehicles. Its main goals are reducing drag and wind noise, minimizing noise emission, and preventing undesired lift forces and other causes of aerodynamic instability at high speeds.

AERODYNAMIC DRAG???• In aerodynamics, aerodynamic

drag is the fluid drag force that acts on any moving solid body in the direction of the fluid free stream flow.

Flow Around A Sedan...• The presence of a trunk at the rear,

the flow separates at the roof end and then spreads downward.

• As a result, the flow around the car is similar to that around a streamline-shaped object with a taper at the rear.

• For this reason, a sedan with a trunk tends to have smaller drag coefficient value than a wagon-type car.

Flow Around A Sedan....

Reduction Of Drag...• There are reported examples of

aircraft wings controlling the boundary layer, in which vortex generators successfully delayed flow separation.

What is a Vortex Generator???

• A vortex generator (VG) is an aerodynamic device, consisting of a small vane usually attached to a lifting surface (or airfoil, such as an aircraft wing) or a rotor blade of a wind turbine. 

• VGs may also be attached to some part of an aerodynamic vehicle such as an aircraft fuselage or a car.

Vortex Generators...

Contd...• Vortex Generators can be used on all

makes and models of Cars, Trucks, SUVs, Trailers, RVs, and any vehicle where there is downward air flow separation. Each wing measures 80mm depth x 25mm height x 31mm width.

Working...• Vortex generators are most often

used to delay flow separation. To accomplish this they are often placed on the external surfaces of vehicles and wind turbine blades.

• VGs are typically rectangular or triangular, about as tall as the local boundary layer, and run in span wise lines usually near the thickest part of the wing.

• Vortex generators are positioned obliquely so that they have an angle of attack with respect to the local airflow in order to create a tip vortex which draws energetic, rapidly moving outside air into the slow-moving boundary layer in contact with the surface.

• A turbulent boundary layer is less likely to separate than a laminar one, and is therefore desirable to ensure effectiveness of trailing-edge control surfaces. Vortex generators are used to trigger this transition.

• Other devices such as vortilons, leading-edge extensions, leading edge cuffs, also delay flow separation at high angles of attack by re-energizing the boundary layer.

Working...

What do they do???

Distribution of velocity using PIV method...

Pressure Distribution of Vehicle...

Applications...

Applications...

Applications...