Ravikumar M.L.

(Photo to be added)


Design Engineer, Infotech Enterprises

Bangalore, India




M.Tech Industrial Training Project (2005):


“Flutter characteristics of aircraft wings and aero engine blade”

A structure with non-circular cross section experiences a fluid force that changes with orientation to the flow. As the structure vibrates, its orientation changes and the fluid flow oscillates if the oscillating fluid force tends to increase vibration, the structure is aerodynamically unstable and very large-amplitude vibration can result. Flutter is the term applied to a class of aero elastic phenomenon of aircraft structure.


Flutter can be defined as the dynamic instability of an elastic body in an air-stream. It is most commonly encountered on the bodies subjected to large latest aerodynamic loads of the lift type, such as aircraft wings, tails and control surfaces.


An airplane wing, as an elastic body, has infinitely many degrees of freedom. But owing to its particular construction, its elastic deformation in chord wise section can usually be described with sufficient accuracy by two quantities: the deflection at a reference point, and the angle of rotation about that point, i.e., the flexural and torsional deformations, respectively. Similarly, for a control surface, such as a flap or an aileron, its freedom to turn about the hinge line is so much more important than its elastic deformation, that ordinarily it is possible to describe the deflection of a control surface simply by angle of rotation about its hinge line. In general, then, it is sufficient to consider three variables in wing flutter: the flexure, the torsion, and the control-surface rotation. A flutter mode consisting of all the three element is called ternary flutter. In special cases, however, two of the variables predominate, and the corresponding flutter modes are called binary flutter modes. Similar consideration applies to airplane tail surfaces.


Blade failures due to fatigue are predominantly vibration related. When a rotor blade passes across the nozzle of the stator, it experiences fluctuating lift and moment forces repeatedly at a frequency given by the number of nozzles multiplied by the speed of a machine. The blades are very flexible members, in the sense that a significant number of their natural frequencies can be in the region of possible nozzle excitation frequencies. It experiences resonance several times during the starting and shutting of the machine, i.e. whenever the instantaneous speed of machine gives rise to nozzle excitation coinciding with the blade frequencies. This is termed as Blade Flutter in an aero engine turbine.


Flutter phenomenon is crucial to the design of airborne vehicles. it is an aircraft performance parameter. Because of this aircraft is going to loose its stability, failure of wings, stiffness of the structure goes down, failure of blades in turbine engine and finally it leads to loss of an aircraft.


Flutter can be reduced by following methods:


1. Shrouded Blade Design: By providing extrusions on both sides of a blade such that when it rotates, each side of extrusions comes in contact with the adjacent blades there by providing no vibration. The shrouds also serve to cut down gas leakage around the tips of the turbine blades. 

2.  Increasing Damping characteristics: Any vibrating structure possesses a certain capacity to dissipate energy, which may be made up of several damping mechanisms. The damping in a turbine blade comes essentially from three different sources i.e. Material damping, Friction damping and Gas damping.


3.   By taking following measures to secure stability in the design of a structure:

·        Provide sufficient stiffness, so that critical speed of aero elastic instabilities is inherently high.

·        Furnish good aerodynamic design, so that the flow remains un-separated in service conditions.

·        Break the inertia and aerodynamic couplings,

·        Provide a servomechanism to control the phase relation ship between various components of motion.


Typical Results of the Eigen-value analysis of the blade:

Material of Blade: Titanium super alloy (Ti-64)


·        M.Tech. in Machine Design at B.M.S. College of Engineering, Bangalore with an aggregate of 72.00%, from VTU, Karnataka.

·        Bachelor of Engineering (Mechanical) Completed in Dec 2001 from P.E.S. Institute of Technology, Bangalore from Bangalore University with Aggregate 77.63%.


Computer Skills:


Platforms : Windows 2000, NT.                                              

Languages: FORTRAN, C, and XML.                                                          

Solid Modeling:   CATIA, V5-R11/R14, Solid Works 2005

FEM Analysis: Ansys 5.4


Work Experience:


1        Presently working as a Design Engineer at Infotech Enterprises Bangalore.

2        Worked as a CAD Engineer at Geometric software solution Ltd., Bangalore.

3        Worked as a Contract Engineer at GTRE Bangalore

4        Worked as a Graduate trainee at Bharath Electronics, Bangalore




Father’s Name: B. Mari Swamy; Languages known: English, Hindi and Kannada;

Hobbies: Traveling, Cricket, chess, Internet, Reading.


Contact Details:


Address: S/O B.MARI SWAMY, No.300, C.A.R.POLICE QUARTERS, M.S.B.LANE, MYSORE ROAD, BANGALORE 560018, Karnataka State, India


Phone: 91 80 26701900; Mobile: 98454 21740


Email ID: ml_ravi3@rediffmail.com; ravikumarml@infotechsw.com



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