Aerodynamic Drag Reduction using

Vortex Generators

Guided by:

Reynold Jose

Asst. Professor

Aue Dept

Presented by:

Ansel J Vattakuzhy

S6 AUE

Roll No: 9

Table of contentObjectiveIntroductionDefinitionExperimental detailsExperiment setupData reductionResults & discussionsConclusionPros & Cons

Objective

To reduce the drag created on an automobile.

To attain high speed stability.

To achieve high vehicle performance.

Introduction

Studies on aerodynamics, originated from aeronautics

and marine applications.

High speed to power ratio.

To achieve high vehicle performance.

Lowering vehicle drag coefficient (Cd), which is about

75 – 80 % of total motion resistance at 100 km/h.

Vortex Generator

Used to delay flow separation.

Typically rectangular or triangular shaped.

Seen on the wings and vertical tails of air liners.

Positioned obliquely to have an angle of attack with local airflow.

Vortex generator by def.

Small, cambered, thin airfoils placed to introduce swirling motions that energize the boundary layer causing a delay in stall.

Experimental detailsDesign of VG Single vane type delta shape. Height of the VG = boundary layer thickness. Thickness of VG fixed at 0.5 mm. L/H ratio as 2 & Interval/height ratio as 6.(fig 1) Single row of 8 VG were positioned.(Fig 2)

Fig 1 Fig 2

Experimental setupScale model: Tata Sumo Grande, scale ratio

1:15.(fig 3)To measure static pres: .2mm holes to place

manometers

Scale model Location of manometers

Continued..Relative air speed measured by micro

manometer.

Expt Procedure

Objective: measure drag force, pressure

variations and relative speed.

Pressure points: front, the roof & rear.

Drag & lift force load cell directly attached to

platform.

Data reductionPressure coefficient

A dimensionless number which describes the relative pressure.Relation b/w dimensional coefficient &dimensional no.:

Cp = (p − p∞)/(ρ∞V2∞)

Dynamic pressure Total pressure = static pressure+ dynamic pressure.

P∞=p+(ρ/2)*u2= const

Contnd…Coefficient of drag(Cd)

relation b/w drag force & force of relative fluid.

D=(1/2) Cdρ AV2

Coefficient of lift(Cl)

relation b/w lift force & force of relative fluid.

L=(1/2)Clρ AV2

Results & Discussion

Pressure coefficient

Dynamic pressure

Coefficient of drag

Coefficient of lift

ConclusionsValue of pressure coefficient without VG is

minimum but its value was observed to be maximum with VG at yaw angle of 15°.

Pressure coefficient increased with inclusion of VG by 17% at velocity 2.42 m/s.

Value of Cd reduced by 90% at velocity 2.42 m/s & minimum 20% reduction in drag for VG at yaw angle 10°.

Different kinds of vortex generators used

Flow effect of VG

Pros And ConsPros Cons

Stall speed reduction (7-21%)

Improved handling qualities

Decrease tire and brake wear

Expensive Makes debugging of the

leading edge difficult Possible source of

vibration Dual instruction and

practice required for full effectiveness

Vortex Generator on cars