Fluid Mechanics Policy Planning and Learning
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CHAPTER TWO - Static Aeroelasticity – Unswept Wing Structural Loads and Performance 21 2.1 Background
Static aeroelasticity – structural loads and performance CHAPTER TWO - Static Aeroelasticity – Unswept wing structural loads and performance 21 2.1 Background ........................................................................................................................... 21 2.1.2 Scope and purpose ....................................................................................................................... 21 2.1.2 The structures enterprise and its relation to aeroelasticity ............................................................ 22 2.1.3 The evolution of aircraft wing structures-form follows function ................................................ 24 2.2 Analytical modeling............................................................................................................... 30 2.2.1 The typical section, the flying door and Rayleigh-Ritz idealizations ................................................ 31 2.2.2 – Functional diagrams and operators – modeling the aeroelastic feedback process ....................... 33 2.3 Matrix structural analysis – stiffness matrices and strain energy .......................................... 34 2.4 An example - Construction of a structural stiffness matrix – the shear center concept ........ 38 2.5 Subsonic aerodynamics - fundamentals ................................................................................ 40 2.5.1 Reference points – the center of pressure..................................................................................... 44 2.5.2 A different -
Manual for Lab #2
CE 321 INTRODUCTION TO FLUID MECHANICS Fall 2009 LABORATORY 3: THE BERNOULLI EQUATION OBJECTIVES To investigate the validity of Bernoulli's Equation as applied to the flow of water in a tapering horizontal tube to determine if the total pressure head remains constant along the length of the tube as the equation predicts. To determine if the variations in static pressure head along the length of the tube can be predicted with Bernoulli’s equation APPROACH Establish a constant flow rate (Q) through the tube and measure it. Use a pitot probe and static probe to measure the total pressure head h Tm and static pressure head h Sm at six locations along the length of the tube. The values of h Tm will show if total pressure head remains constant along the length of the tube as required by the Bernoulli Equation. Using the flow rate and cross sectional area of the tube, calculate the velocity head h Vc at each location. Use Bernoulli’s Equation, h Tm and h Vc to predict the variations in static pressure head h St expected along the tube. Compare the calculated and measured values of static pressure head to determine if the variations in fluid pressure along the length of the tube can be predicted with Bernoulli’s Equation. EQUIPMENT Hydraulic bench with Bernoulli apparatus, stop watch THEORY Considering flow at any two positions on the central streamline of the tube (Fig. 1), Bernoulli's equation may be written as V 2 p V 2 p 1 + 1 + z = 2 + 2 + z (1) 2g γ 1 2g γ 2 1 Bernoulli’s equation indicates that the sum of the velocity head (V 2/2g), pressure head (p/ γ), and elevation (z) are constant along the central streamline. -
Chapter 1 PROPERTIES of FLUID & PRESSURE MEASUREMENT
Fluid Mechanics & Machinery Chapter 1 PROPERTIES OF FLUID & PRESSURE MEASUREMENT Course Contents 1. Introduction 2. Properties of Fluid 2.1 Density 2.2 Specific gravity 2.3 Specific volume 2.4 Specific Weight 2.5 Dynamic viscosity 2.6 Kinematic viscosity 2.7 Surface tension 2.8 Capillarity 2.9 Vapor Pressure 2.10 Compressibility 3. Fluid Pressure & Pressure Measurement 3.1 Fluid pressure, Pressure head, Pascal‟s law 3.2 Concept of absolute vacuum, gauge pressure, atmospheric pressure, absolute pressure. 3.3 Pressure measuring Devices 3.4 Simple and differential manometers, 3.5 Bourdon pressure gauge. 4. Total pressure, center of pressure 4.1 Total pressure, center of pressure 4.2 Horizontal Plane Surface Submerged in Liquid 4.3 Vertical Plane Surface Submerged in Liquid 4.4 Inclined Plane Surface Submerged in Liquid MR. R. R. DHOTRE (8888944788) Page 1 Fluid Mechanics & Machinery 1. Introduction Fluid mechanics is a branch of engineering science which deals with the behavior of fluids (liquid or gases) at rest as well as in motion. 2. Properties of Fluids 2.1 Density or Mass Density -Density or mass density of fluid is defined as the ratio of the mass of the fluid to its volume. Mass per unit volume of a fluid is called density. -It is denoted by the symbol „ρ‟ (rho). -The unit of mass density is kg per cubic meter i.e. kg/m3. -Mathematically, ρ = -The value of density of water is 1000 kg/m3, density of Mercury is 13600 kg/m3. 2.2 Specific Weight or Weight Density -Specific weight or weight density of a fluid is defined as the ratio of weight of a fluid to its volume. -
Upwind Sail Aerodynamics : a RANS Numerical Investigation Validated with Wind Tunnel Pressure Measurements I.M Viola, Patrick Bot, M
Upwind sail aerodynamics : A RANS numerical investigation validated with wind tunnel pressure measurements I.M Viola, Patrick Bot, M. Riotte To cite this version: I.M Viola, Patrick Bot, M. Riotte. Upwind sail aerodynamics : A RANS numerical investigation validated with wind tunnel pressure measurements. International Journal of Heat and Fluid Flow, Elsevier, 2012, 39, pp.90-101. 10.1016/j.ijheatfluidflow.2012.10.004. hal-01071323 HAL Id: hal-01071323 https://hal.archives-ouvertes.fr/hal-01071323 Submitted on 8 Oct 2014 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. I.M. Viola, P. Bot, M. Riotte Upwind Sail Aerodynamics: a RANS numerical investigation validated with wind tunnel pressure measurements International Journal of Heat and Fluid Flow 39 (2013) 90–101 http://dx.doi.org/10.1016/j.ijheatfluidflow.2012.10.004 Keywords: sail aerodynamics, CFD, RANS, yacht, laminar separation bubble, viscous drag. Abstract The aerodynamics of a sailing yacht with different sail trims are presented, derived from simulations performed using Computational Fluid Dynamics. A Reynolds-averaged Navier- Stokes approach was used to model sixteen sail trims first tested in a wind tunnel, where the pressure distributions on the sails were measured. -
Investigation of Sailing Yacht Aerodynamics Using Real Time Pressure and Sail Shape Measurements at Full Scale
18th Australasian Fluid Mechanics Conference Auckland, New Zealand 3-7 December 2012 Investigation of sailing yacht aerodynamics using real time pressure and sail shape measurements at full scale F. Bergsma1,D. Motta2, D.J. Le Pelley2, P.J. Richards2, R.G.J. Flay2 1Engineering Fluid Dynamics,University of Twente, Twente, Netherlands 2Yacht Research Unit, University of Auckland, Auckland, New Zealand Abstract VSPARS for sail shape measurement The steady and unsteady aerodynamic behaviour of a sailing yacht Visual Sail Position and Rig Shape (VSPARS) is a system that is investigated in this work by using full-scale testing on a Stewart was developed at the YRU by Le Pelley and Modral [7]; it is 34. The aerodynamic forces developed by the yacht in real time designed to measure sail shape and can handle large perspective are derived from knowledge of the differential pressures across the effects and sails with large curvatures using off-the-shelf cameras. sails and the sail shape. Experimental results are compared with The shape is recorded using several coloured horizontal stripes on numerical computation and good agreement was found. the sails. A certain number of user defined point locations are defined by the system, together with several section characteristics Introduction such as camber, draft, twist angle, entry and exit angles, bend, sag, Sail aerodynamics is an open field of research in the scientific etc. All these outputs are then imported into the FEPV system and community. Some of the topics of interest are knowledge of the appropriately post-processed. The number of coloured stripes used flying sail shape, determination of the pressure distribution across is arbitrary, but it is common practice to use 3-4 stripes per sail. -
Introduction
CHAPTER 1 Introduction "For some years I have been afflicted with the belief that flight is possible to man." Wilbur Wright, May 13, 1900 1.1 ATMOSPHERIC FLIGHT MECHANICS Atmospheric flight mechanics is a broad heading that encompasses three major disciplines; namely, performance, flight dynamics, and aeroelasticity. In the past each of these subjects was treated independently of the others. However, because of the structural flexibility of modern airplanes, the interplay among the disciplines no longer can be ignored. For example, if the flight loads cause significant structural deformation of the aircraft, one can expect changes in the airplane's aerodynamic and stability characteristics that will influence its performance and dynamic behavior. Airplane performance deals with the determination of performance character- istics such as range, endurance, rate of climb, and takeoff and landing distance as well as flight path optimization. To evaluate these performance characteristics, one normally treats the airplane as a point mass acted on by gravity, lift, drag, and thrust. The accuracy of the performance calculations depends on how accurately the lift, drag, and thrust can be determined. Flight dynamics is concerned with the motion of an airplane due to internally or externally generated disturbances. We particularly are interested in the vehicle's stability and control capabilities. To describe adequately the rigid-body motion of an airplane one needs to consider the complete equations of motion with six degrees of freedom. Again, this will require accurate estimates of the aerodynamic forces and moments acting on the airplane. The final subject included under the heading of atmospheric flight mechanics is aeroelasticity. -
How Do Airplanes
AIAA AEROSPACE M ICRO-LESSON Easily digestible Aerospace Principles revealed for K-12 Students and Educators. These lessons will be sent on a bi-weekly basis and allow grade-level focused learning. - AIAA STEM K-12 Committee. How Do Airplanes Fly? Airplanes – from airliners to fighter jets and just about everything in between – are such a normal part of life in the 21st century that we take them for granted. Yet even today, over a century after the Wright Brothers’ first flights, many people don’t know the science of how airplanes fly. It’s simple, really – it’s all about managing airflow and using something called Bernoulli’s principle. GRADES K-2 Do you know what part of an airplane lets it fly? The answer is the wings. As air flows over the wings, it pulls the whole airplane upward. This may sound strange, but think of the way the sail on a sailboat catches the wind to move the boat forward. The way an airplane wing works is not so different. Airplane wings have a special shape which you can see by looking at it from the side; this shape is called an airfoil. The airfoil creates high-pressure air underneath the wing and low-pressure air above the wing; this is like blowing on the bottom of the wing and sucking upwards on the top of the wing at the same time. As long as there is air flowing over the wings, they produce lift which can hold the airplane up. You can have your students demonstrate this idea (called Bernoulli’s Principle) using nothing more than a sheet of paper and your mouth. -
Darcy's Law and Hydraulic Head
Darcy’s Law and Hydraulic Head 1. Hydraulic Head hh12− QK= A h L p1 h1 h2 h1 and h2 are hydraulic heads associated with hp2 points 1 and 2. Q The hydraulic head, or z1 total head, is a measure z2 of the potential of the datum water fluid at the measurement point. “Potential of a fluid at a specific point is the work required to transform a unit of mass of fluid from an arbitrarily chosen state to the state under consideration.” Three Types of Potentials A. Pressure potential work required to raise the water pressure 1 P 1 P m P W1 = VdP = dP = ∫0 ∫0 m m ρ w ρ w ρw : density of water assumed to be independent of pressure V: volume z = z P = P v = v Current state z = 0 P = 0 v = 0 Reference state B. Elevation potential work required to raise the elevation 1 Z W ==mgdz gz 2 m ∫0 C. Kinetic potential work required to raise the velocity (dz = vdt) 2 11ZZdv vv W ==madz m dz == vdv 3 m ∫∫∫00m dt 02 Total potential: Total [hydraulic] head: P v 2 Φ P v 2 h == ++z Φ= +gz + g ρ g 2g ρw 2 w Unit [L2T-1] Unit [L] 2 Total head or P v hydraulic head: h =++z ρw g 2g Kinetic term pressure elevation [L] head [L] Piezometer P1 P2 ρg ρg h1 h2 z1 z2 datum A fluid moves from where the total head is higher to where it is lower. For an ideal fluid (frictionless and incompressible), the total head would stay constant. -
Compressible Flows for Fluidic Control in Microdevices
COMPRESSIBLE FLOWS FOR FLUIDIC CONTROL IN MICRODEVICES by Dustin S. Chang A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Chemical Engineering) in The University of Michigan 2010 Doctoral Committee: Professor Mark A. Burns, Chair Professor Robert M. Ziff Associate Professor Luis P. Bernal Associate Professor Michael Mayer © Dustin S. Chang 2010 To my mom and dad, Sweson and Chaohui, and my grandparents, Po-High and Peyuk … Thank you for all your sacrifices. ii ACKNOWLEDGEMENTS To the casual observer, a doctoral thesis may appear to be the product of a single dedicated—albeit misguided—individual after multiple years of toil. Anyone that has survived the experience will most assuredly tell you that he could not have done it without the many people who supported him along the way. Beginning long before graduate school, my family has been a constant source of encouragement, well-meaning criticism, and material support. I am hugely grateful for my aunts and uncles who never failed to go the extra mile in taking care of me, teaching me, and challenging me to improve. Aunt Hsueh-Rong, Aunt Nancy, Aunt Chao-Lin, Uncle Jeff, Aunt Tina, and Uncle Ming ... Thank you for your love. The only people potentially deserving greater appreciation than these are my mother and father and my grandparents. I have no doubt that none of my meager accomplishments would have been possible without your prayers and unconditional support, both moral and financial. I also have no doubt that all of the aforementioned people are infinitely more enamored with the idea of a Ph.D. -
Richard Lancaster [email protected]
Glider Instruments Richard Lancaster [email protected] ASK-21 glider outlines Copyright 1983 Alexander Schleicher GmbH & Co. All other content Copyright 2008 Richard Lancaster. The latest version of this document can be downloaded from: www.carrotworks.com [ Atmospheric pressure and altitude ] Atmospheric pressure is caused ➊ by the weight of the column of air above a given location. Space At sea level the overlying column of air exerts a force equivalent to 10 tonnes per square metre. ➋ The higher the altitude, the shorter the overlying column of air and 30,000ft hence the lower the weight of that 300mb column. Therefore: ➌ 18,000ft “Atmospheric pressure 505mb decreases with altitude.” 0ft At 18,000ft atmospheric pressure 1013mb is approximately half that at sea level. [ The altimeter ] [ Altimeter anatomy ] Linkages and gearing: Connect the aneroid capsule 0 to the display needle(s). Aneroid capsule: 9 1 A sealed copper and beryllium alloy capsule from which the air has 2 been removed. The capsule is springy Static pressure inlet and designed to compress as the 3 pressure around it increases and expand as it decreases. 6 4 5 Display needle(s) Enclosure: Airtight except for the static pressure inlet. Has a glass front through which display needle(s) can be viewed. [ Altimeter operation ] The altimeter's static 0 [ Sea level ] ➊ pressure inlet must be 9 1 Atmospheric pressure: exposed to air that is at local 1013mb atmospheric pressure. 2 Static pressure inlet The pressure of the air inside 3 ➋ the altimeter's casing will therefore equalise to local 6 4 atmospheric pressure via the 5 static pressure inlet. -
Introduction to Aerospace Engineering
Introduction to Aerospace Engineering Lecture slides Challenge the future 1 Introduction to Aerospace Engineering Aerodynamics 11&12 Prof. H. Bijl ir. N. Timmer 11 & 12. Airfoils and finite wings Anderson 5.9 – end of chapter 5 excl. 5.19 Topics lecture 11 & 12 • Pressure distributions and lift • Finite wings • Swept wings 3 Pressure coefficient Typical example Definition of pressure coefficient : p − p -Cp = ∞ Cp q∞ upper side lower side -1.0 Stagnation point: p=p t … p t-p∞=q ∞ => C p=1 4 Example 5.6 • The pressure on a point on the wing of an airplane is 7.58x10 4 N/m2. The airplane is flying with a velocity of 70 m/s at conditions associated with standard altitude of 2000m. Calculate the pressure coefficient at this point on the wing 4 2 3 2000 m: p ∞=7.95.10 N/m ρ∞=1.0066 kg/m − = p p ∞ = − C p Cp 1.50 q∞ 5 Obtaining lift from pressure distribution leading edge θ V∞ trailing edge s p ds dy θ dx = ds cos θ 6 Obtaining lift from pressure distribution TE TE Normal force per meter span: = θ − θ N ∫ pl cos ds ∫ pu cos ds LE LE c c θ = = − with ds cos dx N ∫ pl dx ∫ pu dx 0 0 NN Write dimensionless force coefficient : C = = n 1 ρ 2 2 Vc∞ qc ∞ 1 1 p − p x 1 p − p x x = l ∞ − u ∞ C = ()C −C d Cn d d n ∫ pl pu ∫ q c ∫ q c 0 ∞ 0 ∞ 0 c 7 T=Lsin α - Dcosα N=Lcos α + Dsinα L R N α T D V α = angle of attack 8 Obtaining lift from normal force coefficient =α − α =α − α L Ncos T sin cl c ncos c t sin L N T =cosα − sin α qc∞ qc ∞ qc ∞ For small angle of attack α≤5o : cos α ≈ 1, sin α ≈ 0 1 1 C≈() CCdx − () l∫ pl p u c 0 9 Example 5.11 Consider an airfoil with chord length c and the running distance x measured along the chord. -
Activities on Dynamic Pressure
Activities on Dynamic Pressure Sari Saxholm Madrid and Tres Cantos, Spain 15 – 18 May 2017 Dynamic Measurements • Dynamic measurements are widely performed as a part of process control, manufacturing, product testing, research and development activities • Measurements of dynamic pressure have especially a key role in several demanding applications, e.g., in automotive, marine and turbine engines • However, if the sensors are calibrated with static techniques the sensor behavior and reliability of measurement results cannot be ensured in dynamically changing conditions • To guarantee the reliability of results there is the need of traceable methods for dynamic characterization of sensors 2 11th EURAMET General Assembly - 15 - 18 May 2017 EMRP IND09 Dynamic • This EMRP Project (Traceable dynamic measurement of mechanical quantities) was an unique opportunity to develop a new field of metrology • The aim was to develop devices and methods to provide traceability for dynamic measurements of the mechanical quantities force, torque, and pressure • Measurement standards were successfully developed for dynamic pressures for limited range Development work has continued after this EMRP Project: because the awareness of dynamic measurements, and challenges related with the traceability issues, has increased. 3 11th EURAMET General Assembly - 15 - 18 May 2017 Industry Needs • To cover, e.g., the motor industry measurement range better • To investigate the effects of pressure pulse frequency and shape • To investigate the effects of measuring media