... ME2135 & ME2135E Fluid Mechanics II Semester 4 Session 2014/2015 Experiment II Flow over an Airfoil Venue: Fluid Mechanics Lab 2 WS2-01-47 (Ground Floor, Engineering Workshop 2) Tel: 6516-2231 2 January 2015 1 Table of Contents List of Figures 3 Nomenclature 3 1. Introduction 5 1.1 Background 5 1.2 Lift Generation 5 1.3 Objectives and Scope 5 2. Experimental Set-up 6 2.1 Wind Tunnel 6 2.2 Airfoil 6 2.3 Pressure Measurement 6 2.4 Velocity Measurement 6 6 3. Analysis 3.1 Free Stream Velocity 6 3.2 Pressure Coefficient 7 3.3 Force Coefficients 7 3.4 Trapezoidal Method 8 3.5 Thin Airfoil Theory 9 4. Procedure 9 4.1 Experiment 9 4.2 Tables 10 5. Results and Discussion 10 5.1 Results 10 5.2 Discussion 11 6. Conclusions and Recommendations 11 6.1 Conclusions 11 6.2 Recommendations 11 References 12 Figures 12 Tables 16 Appendix A 19 2 List of Figures Figure 1 a) Airfoil Terminology; b) Pressure Gradient across a Curved Streamline; c) Streamlines over an Airfoil 12 Figure 2 Airfoil in the Wing Tunnel 13 Figure 3 Schematic Diagram (Side View) of Pressure Measurement 13 Figure 4 Forces and Pressure on an Airfoil 14 Figure 5 Pressure Distribution around an Airfoil; at a=10° and Re=2.33x105 15 Figure 6 Area between Two Curves using Trapezoidal...
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...2nd Flow Control Conference 28 Jun - 1 Jul 2004 / Portland, Oregon AIAA-2004-2319 Aerodynamic Performance of Biological Airfoils Abel Vargas* and Rajat Mittal† The George Washington University, Washington, D.C., 20052 Experimental studies on static, non-flapping dragonfly wings have shown favorable aerodynamic performance at low Reynolds number (Re ≤ 10,000). High lift is hypothesized to arise from the dragonfly’s pleated wing structure. A numerical study of flow past a modeled dragonfly wing section as well as its comparison to a corresponding profiled airfoil and a flat plate were conducted at Re = 10,000. The main focus of the current investigation was to determine the primary flow features and mechanisms that are responsible for the enhanced performance of these biological wing sections at these relatively low Reynolds numbers. A time-accurate Cartesian grid based Navier-Stokes immersed boundary solver was utilized in the current study. The numerical results indicate that the pleated airfoil at a zero degree angle-of-attack generates the least drag despite its unconventional shape. Additionally, a higher transitory lift is produced by the pleated airfoil at a five degree angleof-attack when compared to the profiled airfoil. Nomenclature c CD CDs CDp CL CLs CLp P Re τ t t* ui = = = = = = = = = = = = = = = = chord length drag coefficient shear drag coefficient pressure drag coefficient lift coefficient shear lift coefficient pressure lift coefficient Pressure Reynolds...
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...Attack and lift 5 The Flow of Fluids 6 Lift 6 Resulting Lifting Force 7 Pressure Distribution 7 Center of Pressure 8 Calculations & Results 8 Discussion 13 Conclusion 13 References 13 Introduction Aerodynamics is a branch of mechanics concerned with the motion of a fluid continuum the action of applied forces. The motion and general behaviour of a fluid is governed by the fundamental laws of classical mechanics and thermodynamics and plays an important role in such diverse fields as biology, meteorology, chemical engineering, and aerospace engineering. An introductory text on fluid mechanics, such as , surveys the basic concepts of fluid dynamics and the various mathematical models used to describe fluid flow under different restrictive assumptions. The objectives of this experiment are to investigate the way in which the static pressure varies on the surface of an aerofoil in low speed flow, and to deduce the lift force acting on the aerofoil. An aerofoil with a symmetrical section is used for the experiment, which is conducted in a wind tunnel at a wind speed low enough for the flow to be treated as incompressible. From the measured distribution of surface pressure around the aerofoil at a small angle of incidence, the lift will be calculated by numerical integration, and compared with the predictions of inviscid flow theory. The measured chord wise load distribution will also be compared with the results given for inviscid flow by thin aerofoil theory...
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...Abstract: In this experiment, the use of a scale model airfoil section of an aircraft wing will be analyzed in a wind tunnel. The basic physical laws of engineering and science shall be applied to verify and to understand the principles of flight. A dimensional analysis will be applied to the model airfoil to represent a full-scale wing prototype. The basics of aerodynamics, as applied to standard NACA airfoil configurations, shall be applied to establish performance data regarding lift, drag and stall with respect to the various angles attack demonstrated throughout the experiment at a number of air speeds. It should be noted that the Cessna 152 trainer aircraft uses a NACA 2412 airfoil, which is slightly thinner than the NASA 2415 airfoil currently available in this laboratory. Other airfoil models used in this laboratory include the NACA 4415 (normally used on the Lake Amphibious aircraft) and the NACA 0015 (used on helicopter blades and some acrobatic aircraft). The NACA 4415 is a very high lift airfoil designed to lift aircraft out of water quickly. Table of Content Abstract………..........................................................................................................................ii 1. Introduction....................................................................................................................4 2. Theory.......................................................................................................................
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...Distribution and Lift for an Airfoil Purpose The objectives of the experiment are to examine the surface pressure distribution and to compute the lift force acting on the airfoil. Test Design A body immersed in a flowing fluid is exposed to both pressure and viscous forces. The sum of the forces that acts normal to the free-stream direction is the lift, and the sum that acts parallel to the free-stream direction is the drag. The geometric and dynamic characteristics of airfoils are shown in Figure 1. This experiment is concerned with computation of the lift on a stationary airfoil mounted in the test section of a wind tunnel. We will consider only two-dimensional airfoils where tip and root effects are neglected. Because the velocity of the flow over the top of the airfoil is greater than the free-stream velocity, the pressure over the top is negative. This follows directly from the application of Bernoulli’s equation. Similarly the velocity along the underside of the airfoil is less than the free-stream velocity and the pressure there is positive. Hence, both the negative pressure over the top and the positive pressure along the bottom contribute to the lift. There are a variety of ways to measure lift. In this experiment, the lift force, L, on the airfoil will be determined by integration of the measured pressure distribution over the airfoil’s surface. Typical pressure distribution on an airfoil and its projection on the airfoil normal are shown in Figure...
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...School of Innovation, Design and Engineering Bachelor Thesis in Aeronautical Engineering 15 credits, Basic level 300 Investigation of Different Airfoils on Outer Sections of Large Rotor Blades Authors: Torstein Hiorth Soland and Sebastian Thuné Report code: MDH.IDT.FLYG.0254.2012.GN300.15HP.Ae Sammanfattning Vindkraft står för ca 3 % av jordens produktion av elektricitet. I jakten på grönare kraft, så ligger mycket av uppmärksamheten på att få mer elektricitet från vindens kinetiska energi med hjälp av vindturbiner. Vindturbiner har använts för elektricitetsproduktion sedan 1887 och sedan dess så har turbinerna blivit signifikant större och med högre verkningsgrad. Driftsförhållandena förändras avsevärt över en rotors längd. Inre delen är oftast utsatt för mer komplexa driftsförhållanden än den yttre delen. Den yttre delen har emellertid mycket större inverkan på kraft och lastalstring. Här är efterfrågan på god aerodynamisk prestanda mycket stor. Vingprofiler för mitten/yttersektionen ...
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...FUNDAMENTALS OF GAS TURBINE ENGINES INTRODUCTION The gas turbine is an internal combustion engine that uses air as the working fluid. The engine extracts chemical energy from fuel and converts it to mechanical energy using the gaseous energy of the working fluid (air) to drive the engine and propeller, which, in turn, propel the airplane. THE GAS TURBINE CYCLE The basic principle of the airplane turbine engine is identical to any and all engines that extract energy from chemical fuel. The basic 4 steps for any internal combustion engine are: 1. Intake of air (and possibly fuel). 2. Compression of the air (and possibly fuel). 3. Combustion, where fuel is injected (if it was not drawn in with the intake air) and burned to convert the stored energy. 4. Expansion and exhaust, where the converted energy is put to use. In the case of a piston engine, such as the engine in a car or reciprocating airplane engine, the intake, compression, combustion, and exhaust steps occur in the same place (cylinder head) at different times as the piston goes up and down. In the turbine engine, however, these same four steps occur at the same time but in different places. As a result of this fundamental difference, the turbine has engine sections called: 1. 2. 3. 4. The inlet section The compressor section The combustion section (the combustor) The turbine (and exhaust) section. The turbine section of the gas turbine engine has the task of producing usable output shaft power to drive the propeller...
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...Ansys Workbench Basics Guide Suhail Mahmud and Mohamad Wissam Ansys Workbench Basics Guide Suhail Mahmud Mostafa Mohamad Wissam Farhoud December - 2013 1 Ansys Workbench Basics Guide Suhail Mahmud and Mohamad Wissam Abstract With the emerging importance of CFD and finite element analyses, it is of great necessity that engineering students get a good base of knowledge on one of the most used software packages in the industry of simulation, ANSYS. This brief tutorial states a few simple examples of the main applications of the software package ANSYS and highlights some of the possible problems students may face during their journey in discovering this application. The flow of information is structured that the reader gets an understanding of how important ANSYS is, and how it works and what type of machines are needed for the student level research expected. Then the tutorial goes on with simple straight forward examples of structural and fluid physics simulated using the ANSYS package. Eventually, the tutorial addresses the most important problems generally faced by the students such as unsuccessful meshing, or divergent solutions. Disclaimer It is extremely important to note two points while following this tutorial: The knowledge contained in this paper is by no means, accepted as mainstream, or an industry best practice. It is merely the product of the experience of senior engineering students who explored the program and desired to share their experience...
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...1. 1.1 2. 2.1 2.2 2.3 2.4 3. 3.1 3.2 3.3. 3.4. 4. INTRODUCTION................................................................................................. 2 OBJECTIVES ................................................................................................... 3 GROUND EFFECT AERODYNAMICS.............................................................. 4 CHORD DOMINATED GROUND EFFECT ................................................... 4 SPAN DOMINATED GROUND EFFECT....................................................... 5 AERODYNAMIC CENTERS IN GROUND EFFECT..................................... 6 AERODYNAMIC EFFICIENCY IN GROUND EFFECT ............................... 7 EKRANOPLANS.................................................................................................. 9 CONFIGURATION LAYOUT ......................................................................... 9 POWER AUGMENTATION RAM (PAR)..................................................... 12 LONGITUDINAL STABILITY...................................................................... 14 LATERAL STABILITY ................................................................................. 15 1. INTRODUCTION Wing-in-ground effect applies to vehicles design to fly at very low altitudes to take the advantage of increased in aerodynamic lift and reduced drag which occurs when a wing is in ground effect. The phenomenon of ground effect was observed as early as the Wright Brothers’ Wright Flyer I which...
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...1 INTRODUCTION TO WIND ENERGY........................................................................................................1 1.1 What is wind energy..................................................................................................................................1 1.2 Why use wind energy ................................................................................................................................1 Why choose wind over conventional fuel sources .........................................................................1 1.2.2 Why choose wind over other renewable energy technologies............................................................1 1.3 The history and rise of wind energy ..........................................................................................................2 1.3.1 The first windmills were for mechanical power generation ...............................................................2 1.3.2 Electrical power generation ................................................................................................................3 1.4 Wind energy in Australia ..........................................................................................................................6 1.5 Wind energy in the future..........................................................................................................................7 1.5.1 Onshore wind energy ...............................................
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...hours dual (2 hours dual cross country with two 30 min legs) 5 hours PIC Flight Test:________ % Private Pilot Licence Age: _______ Medical Category: __________ Written Test _______% (Must have valid Medical, ground school time and 10 hours flight time) Training: 45 hours total time 15 hours dual (3 hours dual cross country, 5 hours instrument training). 12 hours PIC (5 hours PIC cross country, including a 150 nm route with 2 stops) Flight Test: ______ % Night Rating Must hold a Private Pilot Licence Training: ______ hours of flight training consisting of: 5 more hours of instrument training 10 hours night (5 dual 2 hours cross country, 5 Solo, 10 takeoffs and landings) No Flight Test or Written Test VFR Over-The- Top (VFR OTT) Must hold a Private Pilot Licence Training: Minimum of 15 hours dual instrument time Multi-Engine Rating Training: No minimum hours required Flight Test Required Instrument Rating Group 1: _______; Group 2 ___________ Written and flight test required Training: 40 hours instrument time required (1 dual cross country 100 nm) Minimum 50 hour cross-country PIC AIRFRAMES AND PARTS OF AN AIRPLANE Basic Definitions Airframe: Structure of an aircraft without engines, power plants or instruments Fuselage: the body of the aircraft to which other components are attached, used to accommodate crew, passengers and cargo Wing: Device employed to develop lift on an airplane Ailerons: Surfaces hinged...
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...about half the speed of sound so at flight speeds lower than this the flow will accelerate along the inlet and at higher flight speeds it will slow down. Thus the internal profile of the inlet has to accommodate both accelerating and diffusing flow without undue losses. For supersonic aircraft, the inlet has features such as cones and ramps to produce the most efficient series of shockwaves which form when supersonic flow slows down. The air slows down from the flight speed to subsonic velocity through the shockwaves, then to about half the speed of sound at the compressor through the subsonic part of the inlet. The particular system of shockwaves is chosen, with regard to many constraints such as cost and operational needs, to minimize losses which in turn maximizes the pressure recovery at the compressor. An intake, or especially for aircraft inlet, is an air intake for an engine. Because the modern internal combustion engine is in essence a powerful air pump, like the exhaust system on an engine, the intake must be carefully engineered and tuned to provide the greatest efficiency and power. An ideal intake system should increase the velocity of the air until it travels into the combustion chamber, while minimizing turbulence and restriction of flow. With the development of jet engines and the subsequent ability of aircraft to travel at supersonic speeds, it was necessary to design inlets to provide the flow required by the engine...
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...of its flight. A returning boomerang is designed to return to the thrower. It is well known as a weapon used by Indigenous Australians for hunting”. Ok so by definition boomerangs fly because: “Returning boomerangs fly and are examples of the earliest heavier-than-air man-made flight. A returning boomerang has two or more airfoil wings arranged so that the spinning creates unbalanced aerodynamic forces that curve its path so that it travels in an elliptical path and returns to its point of origin when thrown correctly. While a throwing stick can also be shaped overall like a returning boomerang, it is designed to travel as straight as possible so that it can be aimed and thrown with great force to bring down game. Its surfaces therefore are symmetrical and not uneven like the aerofoils which give the returning boomerang its characteristic curved flight. by wiki” They also return due to the shaping on the edge of wings, a physicist article said “The returning boomerang is most commonly two wings jointed at angle between 80° and 120°, however, some newer boomerangs have more than two wings. The combination of spin and forward motion create an uneven lift over...
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...SPIN AWARENESS AND AVOIDANCE Objective To teach the student the avoidance and proper recovery from spins. Elements • Uncoordinated stalls • Aerodynamics of a spin • Recovery procedure Schedule Discussion 0:30 Equipment Model airplane Instructor Actions Discuss what is a spin (an aggravated stall that results in autorotation). Autorotation results from unequal angles of attack on the wings. The key is aggravated (i.e. uncoordinated). Draw or show the corkscrew/helical flight path of a spin. The difference between a spin and a steep spiral: spin—airspeed low, wings stalled; spiral—airspeed increasing, not stalled. Discuss the aerodynamics of a spin. Draw a wing in straight-and-level flight and in slow flight. Use actual angles of attack. Typical light aircraft wings stall at 18-22º. How can you enter a spin? Wing exceeds critical angle of attack with yaw acting on aircraft (uncoordinated). That is, a stall when in a slipping or skidding turn. Danger of base to final turn—cross controlled stall leading to spin. The high wing has the greatest lift due to the greater airspeed, and overall less drag and lower angle of attack. The low wing has the least lift (due to lower airspeed) and greatest parasitic drag due to its higher angle of attack. Center of gravity affects the spin characteristics. An aft CG makes spin recovery more difficult. The worst case is the aircraft may enter into a flat spin if CG is too far back, making recovery impossible. Center...
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...answer “shooting stars” my father explaining to me how friction causes the object to get hot and burn. When I got a little older I realized that I was in fact, too short to be an astronaut. At the same time this was happening though I was getting ever more involved with the different breeds of robotics with which I had gotten entangled. I had done FIRST Lego League in elementary school before moving to VEX and finally to FIRST robotics. I loved it the whole time, entranced with the little moving parts and the idea that they all worked together to create something that could fly. I started building cars with my school’s Electric Race team. I looked at the Aerodynamics and saw how the wind was flowing over. It was through FIRST and race team in which I learned CAD and got to see flow design - a wind tunnel simulator. I spent a week drawing up...
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