JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD

UNIT - I

Atmospheric Winds and Atmospheric Boundary Layer: Causes of wind thermal drive, Coriolis effect, pressure gradient effect, Geotrophic winds. Land and sea breeze, mountain winds, thermals, cause of turbulence at ground level. Atmospheric boundary layer, velocity profile laws-effects of terrain on atmospheric boundary Layer. Wind tunnels basic features and components. Wind tunnel models-role of non-dimensional groups. Creation of atmospheric boundary Layer type flow in a wind tunnel.

UNIT - II

Wind Energy: Ship propulsion-sails-lift and drag translators-modern yachts. Horizontal (HAWT) and vertical axis (VAWT) wind turbines-history, first example of automatic feedback control for yaw in 16th century English windmills, classification. Horizontal axis wind turbine (HAWT- elementary actuator disc theory-Betz coefficient. Definition of power coefficient &torque coefficient for all wind turbines. Working principle, power coefficients, tip speed ratio explanation: by introductory blade element theory- conventional horizontal axis wind turbine (HAWT), savonious vertical axis wind turbine (VAWT), Darries VAWT, merits and demerits of HAWTs and VAWTs.

UNIT - III

Vehicle Aerodynamics: relative importance of rolling resistance and aerodynamics resistance, power requirements and drag coefficients of automobiles-notch front and notch rear wind screens versus streamlined shape, Causes of vortex formation and drag—attached transverse vortex , trailing vortex, trailing vortex drag-effect of floor height on lift, effects of cut bank angle, rear end taper: side panels and bottom. Effects of chamfering of edges and cambering of roof & side panels. Racing cars-traction and steering strip and use of aerofoils, high cornering seed. Commercial transport vehicles-drag reduction on buses and tucks; driver cabin and trailer combinations.

UNIT - IV

Building Aerodynamics: Use of light weight components in modern buildings, pressure distribution on low-rise buildings, wind forces on buildings-aerodynamics of flat plate and circular cylinder , critical Reynold’s no, sub -, super- & ultra critical Reynold’s No. Role of wind tunnel requirements in determining shape factors (Drag coefficients) of building/structure shapes such as circular cylinder (chimneys & towers), rectangle, I- shape, L-shape, H-shape etc. vortex shedding & transverse oscillating loads. Slenderness ratio & correction factor. Special problems of tall buildings, interference effect of building.

R16 B.TECH AERONAUTICAL ENGG.

UNIT - V

Flow Induced Vibrations: Classification – vortex induced vibration & flow induced instability such as Galloping & Stall flutter. Effects of Reynolds number on wake formation of bluff shapes. Vortex induced vibration – experimental determination of strouhal numbers for different shapes such as circular cylinder, square, rectangle, L-shape ect, universal strouhal number, unsteady Bernoulli equation, concept of added mass, Resonance, fluid – structure interaction – effect of transverse cylinder motion on flow and wake, “lock-in” vortex shedding near resonant frequency, experimental evidence of cylindrical motion influencing flow and thereby reducing strength of shed vortices. Methods of suppression of vortex induced vibration. Galloping & Stall flutter – motion of one degree-of-freedom, quasi steady flow assumption, Aerodynamic damping, Galloping – force in the direction of plunging (transverse motion ) and positive force coefficient, critical speed, Galloping of transmission wire with winter ice, stall flutter of airfoils.

TEXT BOOKS:

• 1. Blevins R.D Flow Induced Vibrations, van Nostard, 1990.
• 2. Sachs. P. Wind Forces in Engineering, Pergamon press 1988.
• 3. Calvert N.G. Wind Power Principles, Charles Griffin & co. London, 1979.

REFERENCES:

• 1. Scorer R.S. Environmental Aerodynamics, Ellis Harword Ltd, England, 1978.
• 2. Sorvan, M. Aerodynamics Drag Mechanisms of Bluff Bodies and Road vehicles, plenum press, N.Y.1978. R16 B.TECH AERONAUTICAL ENGG.