Aerodynamics project ideas

Numerical investigation into energy extraction of flapping airfoil with Gurney flaps

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A new type of Gurney flap is proposed.

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Application of Gurney flaps on a flapping airfoil for energy extraction is studied numerically.

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The effects of various motion parameters and Gurney flap heights are investigated.

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The mechanisms of energy extraction enhancement are analyzed.

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Abstract

A new type of Gurney flap is applied for energy extraction enhancement of a flapping airfoil. Two-dimensional Navier-Stokes simulations at Re = 10⁴ are conducted to study the effect of Gurney flaps with various heights. The investigations are undertaken over a wide range of kinematic parameters (reduced frequency k, pitching amplitude θ₀). Numerical results show that the application of a Gurney flap notably increases the maximum output power and efficiency compared with a clean NACA0012 airfoil. By affecting the flow structure and the pressure distribution around the trailing edge of the airfoil, the Gurney flap is beneficial to the lift force generation, thus leading to a higher power coefficient. The maximum power coefficient increases with Gurney flap height h_g at first between h_g = 0c–0.3c (c is the airfoil chord length), while a further increase in h_g provides no further energy extraction enhancement. Besides, the increasing h_g results in stronger trailing edge vortices and higher drag force.

Keywords

• Flapping airfoil;
• Energy extraction;
• Gurney flap

Automatic modelling of airfoil data points

Universidad Politécnica de Madrid. (UPM), Avenida Arco de la Victoria 4, 28040 Madrid, Spain

 

Received 23 February 2016, Revised 14 June 2016, Accepted 21 June 2016, Available online 27 June 2016

 Abstract

This paper presents a computer-based technique to construct B-spline parametric models from a large set of airfoil data points, with a reduced number of parameters involved in the geometric representation of the airfoil profile. The proposed method uses different techniques related with the B-spline properties adapted to the geometry of an airfoil (a thin section with great changes of curvature) and produces a B-spline curve that is close to the data points maintaining a maximum tolerance distance. This curve can be used for calculations and is expected to provide a good framework for aerodynamic or hydrodynamic optimization, based on its reduced number of geometric parameters and on its calculation time, when compared with other methodologies. The method stresses the fitting of the airfoil's leading edge, which has a significant impact on the properties of the airfoil. B-spline curves and surfaces are used in this method because they are widely used in CAD-CAM software products and can be easily exported to other programs.

Keywords

• Airfoils;
• B-splines;
• Parametric design;
• Least squared fitting

 

Flight Dynamics Problems and solution - part 1

Flight Dynamics Problems and solution - part 1
[Useful for GATE - AEROSPACE ENGINEERING (AE )]

An aircraft cruises at a calibrated airspeed of 320 kt in FL 200. The outside air temperature is -23 °C. a) Calculate the air pressure p in FL 200.
b) Calculate the air density r in FL 200 under given conditions.
c) Determine the equivalent airspeed EAS from a suitable diagram.
d) Calculate the equivalent airspeed EAS.
e) Calculate the true airspeed TAS.
f) Calculate the Mach number.

An aircraft is equipped with a wing of symmetrical airfoils:-

During an IFR flight, a passenger looks out the window while relaxing in his seat. He observes a turn and estimates the bank angle to be 30°. At the same time, the passenger observes the free surface of the orange juice in his glass: it is parallel to the tray.
a) The passenger assumes the turn being flown as a rate one turn. Explain the term rate one turn. Why is it correct to assume a rate one turn.
b) The passenger assumes the turn being flown as a coordinated turn. Explain the term coordinated turn. Why is it correct to assume a coordinated turn.
c) Calculate the aircraft's true airspeed

An aerobatic airplane flies a perfect circular looping. The pilot reads an altitude of 5000 ft at the highest point of the looping and an altitude of 4000 ft a the lowest point of the looping. The looping is flown at such a speed that the lowest load factor in the looping is n = 0. Assume that aircraft speed is nearly constant in the looping. a) During which part of the looping does the airplane experience the highest load factor? b) What is the aircraft's speed in the looping? c) Calculate the highest load factor n during the looping.

A jet cruises with constant lift coefficient and constant Mach number of 0.82 in the stratosphere. The take-off mass with full fuel tanks is 271000 kg, the maximum fuel volume is 135000 liters, fuel density is 800 kg/m³. The specific fuel consumption is 16 mg/(Ns). The aircraft has a specified range of 7200 NM.
a) Write down the appropriate equation for these flight conditions from which the range can be calculated. How is this equation named?
b) Calculate the aircraft's mass without fuel.
c) On its fuel reserves, the aircraft could fly additional 920 NM plus further 30 min. How far could the aircraft fly in these 30 min. if we assume that the 30 min. are also flown at cruise speed? How far could the aircraft fly on its fuel reserves?
d) Calculate the aircraft's lift-to-drag ratio.

Derive an equation for the range of a jet aircraft in a (shallow) steady climb with constant airspeed and constant lift coefficient.

GATE Aerospace Engg Tutorial Part - 2

GATE Aerospace Engg Tutorial Part-1

Space flight mcq

1			A satellite ______.
			A)	orbits around a larger body
			B)	is the path of a satellite
			C)	is the path of an object
			D)	can be dangerous
2			An orbit ______.
			A)	0rbits around a larger body
			B)	is the path of a satellite
			C)	is the path of an object
			D)	can be dangerous
3			A trajectory ______.
			A)	orbits around a larger body
			B)	is the path of a satellite
			C)	is the path of an object
			D)	can be dangerous
4			Reentry ______.
			A)	orbits around a larger body
			B)	is the path of a satellite
			C)	is the path of an object
			D)	can be dangerous
5			Staging ______.
			A)	keeps things moving or stationary
			B)	helps get rockets into space
			C)	draws objects toward the earth
			D)	is affected by gravity and inertia
6			Gravity ______.
			A)	keeps things moving or stationary
			B)	helps get rockets into space
			C)	draws objects toward the earth
			D)	is affected by gravity and inertia
7			Inertia ______.
			A)	keeps things moving or stationary
			B)	helps get rockets into space
			C)	draws objects toward the earth
			D)	is affected by gravity and inertia
8			A trajectory ______.
			A)	keeps things moving or stationary
			B)	helps get rockets into space
			C)	draws objects toward the earth
			D)	is affected by gravity and inertia
9			A space hazard ______.
			A)	can be something that is NOT in space
			B)	is a hazard
			C)	can be lack of radiation
			D)	is called "the bends"
10			Air pressure ______.
			A)	can be something that is NOT in space
			B)	is a hazard
			C)	can be lack of radiation
			D)	is called "the bends"