Investigation of Sailing Yacht Aerodynamics Using Real Time Pressure and Sail Shape Measurements at Full Scale
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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. -
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. -
TOTAL ENERGY COMPENSATION in PRACTICE by Rudolph Brozel ILEC Gmbh Bayreuth, Germany, September 1985 Edited by Thomas Knauff, & Dave Nadler April, 2002
TOTAL ENERGY COMPENSATION IN PRACTICE by Rudolph Brozel ILEC GmbH Bayreuth, Germany, September 1985 Edited by Thomas Knauff, & Dave Nadler April, 2002 This article is copyright protected © ILEC GmbH, all rights reserved. Reproduction with the approval of ILEC GmbH only. FORWARD Rudolf Brozel and Juergen Schindler founded ILEC in 1981. Rudolf Brozel was the original designer of ILEC variometer systems and total energy probes. Sadly, Rudolph Brozel passed away in 1998. ILEC instruments and probes are the result of extensive testing over many years. More than 6,000 pilots around the world now use ILEC total energy probes. ILEC variometers are the variometer of choice of many pilots, for both competition and club use. Current ILEC variometers include the SC7 basic variometer, the SB9 backup variometer, and the SN10 flight computer. INTRODUCTION The following article is a summary of conclusions drawn from theoretical work over several years, including wind tunnel experiments and in-flight measurements. This research helps to explain the differences between the real response of a total energy variometer and what a soaring pilot would prefer, or the ideal behaviour. This article will help glider pilots better understand the response of the variometer, and also aid in improving an existing system. You will understand the semi-technical information better after you read the following article the second or third time. THE INFLUENCE OF ACCELERATION ON THE SINK RATE OF A SAILPLANE AND ON THE INDICATION OF THE VARIOMETER. Astute pilots may have noticed when they perform a normal pull-up manoeuvre, as they might to enter a thermal; the TE (total energy) variometer first indicates a down reading, whereas the non-compensated variometer would rapidly go to the positive stop. -
Fluid Mechanics Policy Planning and Learning
Science and Reactor Fundamentals – Fluid Mechanics Policy Planning and Learning Fluid Mechanics Science and Reactor Fundamentals – Fluid Mechanics Policy Planning and Learning TABLE OF CONTENTS 1 OBJECTIVES ................................................................................... 1 1.1 BASIC DEFINITIONS .................................................................... 1 1.2 PRESSURE ................................................................................... 1 1.3 FLOW.......................................................................................... 1 1.4 ENERGY IN A FLOWING FLUID .................................................... 1 1.5 OTHER PHENOMENA................................................................... 2 1.6 TWO PHASE FLOW...................................................................... 2 1.7 FLOW INDUCED VIBRATION........................................................ 2 2 BASIC DEFINITIONS..................................................................... 3 2.1 INTRODUCTION ........................................................................... 3 2.2 PRESSURE ................................................................................... 3 2.3 DENSITY ..................................................................................... 4 2.4 VISCOSITY .................................................................................. 4 3 PRESSURE........................................................................................ 6 3.1 PRESSURE SCALES ..................................................................... -
Bernoulli? Perhaps, but What About Viscosity?
Volume 6, Issue 1 - 2007 TTTHHHEEE SSSCCCIIIEEENNNCCCEEE EEEDDDUUUCCCAAATTTIIIOOONNN RRREEEVVVIIIEEEWWW Ideas for enhancing primary and high school science education Did you Know? Fish Likely Feel Pain Studies on Rainbow Trout in the United Kingdom lead us to conclude that these fish very likely feel pain. They have pain receptors that look virtually identical to the corresponding receptors in humans, have very similar mechanical and thermal thresholds to humans, suffer post-traumatic stress disorders (some of which are almost identical to human stress reactions), and respond to morphine--a pain killer--by ceasing their abnormal behaviour. How, then, might a freshly-caught fish be treated without cruelty? Perhaps it should be plunged immediately into icy water (which slows the metabolism, allowing the fish to sink into hibernation and then anaesthesia) and then removed from the icy water and placed gently on ice, allowing it to suffocate. Bernoulli? Perhaps, but What About Viscosity? Peter Eastwell Science Time Education, Queensland, Australia [email protected] Abstract Bernoulli’s principle is being misunderstood and consequently misused. This paper clarifies the issues involved, hypothesises as to how this unfortunate situation has arisen, provides sound explanations for many everyday phenomena involving moving air, and makes associated recommendations for teaching the effects of moving fluids. "In all affairs, it’s a healthy thing now and then to hang a question mark on the things you have long taken for granted.” Bertrand Russell I was recently asked to teach Bernoulli’s principle to a class of upper primary students because, as the Principal told me, she didn’t feel she had a sufficient understanding of the concept. -
Fluids Lab 1 – Lecture Notes
Fluids Lab 1 – Lecture Notes 1. Bernoulli Equation 2. Pitot-Static Tube 3. Airspeed Measurement 4. Pressure Nondimensionalization References: Anderson 3.2-3.5, Denker 3.4 ( http://www.av8n.com/how/ ) Bernoulli Equation Definition For every point s along a streamline in frictionless flow with constant density ρ, the local speed V (s)= |V~ | and local pressure p(s) are related by the Bernoulli Equation 1 p + ρV 2 = p (1) 2 o This po is a constant for all points along the streamline, even though p and V may vary. This is illustrated in the plot of p(s) and po(s) along a streamline near a wing, for instance. 1ρ 2 2 V po p s s Standard terminology is as follows. p = static pressure 1 ρV 2 = dynamic pressure 2 po = stagnation pressure, or total pressure Also, a commonly-used shorthand for the dynamic pressure is 1 2 q ≡ ρV 2 so we can also write the Bernoulli equation in the following compact form. p + q = po 1 Uniform Upstream Flow Case Many practical flow situations have uniform flow somewhere upstream, with V~ (x, y, z)= V~∞ and p(x, y, z) = p∞ at every upstream point. This uniform flow can be either at rest with V~∞ ≃ 0 (as in a reservoir), or be moving with uniform velocity V~∞ =6 0 (as in a upstream wind tunnel section), as shown in the figure. V(x,y,z) V(x,y,z) p(x,y,z) p(x,y,z) V = 0 V = const. p = const. p = const. -
Aerospace Micro-Lesson Aiaa
AIAA AEROSPACE MICRO-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 AIR SPEED One of the most important pieces of knowledge for any pilot is the speed of an aircraft. There are two ways to measure the speed of an airplane: airspeed and ground speed. Airspeed is the speed of the airplane with respect to the air through which it is flying; ground speed is its speed relative to the ground over which it is flying. Airspeed is important when calculating lift and drag; ground speed is important when calculating flight times between different places. Calculating speeds is a major part of designing and flying aircraft. G RADES K-2 Flying a paper airplane on a windy day shows the difference between airspeed and ground speed very well. Fly the paper airplane indoors—in the classroom or down the hall, if you have permission—and note how far it goes and in what direction. Then go outside to a place where the wind is blowing and fly the paper airplane again. There does not need to be much wind at all. For the clearest illustration of the difference, launch the paper airplane at right angles to the wind, so that it flies through a crosswind and gets blown sideways. The airspeed is the same as it was when it flew indoors, but the ground speed now has a serious sideways component. You can also launch it into the wind and downwind, showing that even though the airspeed is the same, the wind always adds a component to the ground speed in the direction in which it is blowing. -
Glider Handbook, Chapter 4: Flight Instruments
Chapter 4 Flight Instruments Introduction Flight instruments in the glider cockpit provide information regarding the glider’s direction, altitude, airspeed, and performance. The categories include pitot-static, magnetic, gyroscopic, electrical, electronic, and self-contained. This categorization includes instruments that are sensitive to gravity (G-loading) and centrifugal forces. Instruments can be a basic set used typically in training aircraft or a more advanced set used in the high performance sailplane for cross- country and competition flying. To obtain basic introductory information about common aircraft instruments, please refer to the Pilot’s Handbook of Aeronautical Knowledge (FAA-H-8083-25). Instruments displaying airspeed, altitude, and vertical speed are part of the pitot-static system. Heading instruments display magnetic direction by sensing the earth’s magnetic field. Performance instruments, using gyroscopic principles, display the aircraft attitude, heading, and rates of turn. Unique to the glider cockpit is the variometer, which is part of the pitot-static system. Electronic instruments using computer and global positioning system (GPS) technology provide pilots with moving map displays, electronic airspeed and altitude, air mass conditions, and other functions relative to flight management. Examples of self-contained instruments and indicators that are useful to the pilot include the yaw string, inclinometer, and outside air temperature gauge (OAT). 4-1 Pitot-Static Instruments entering. Increasing the airspeed of the glider causes the force exerted by the oncoming air to rise. More air is able to There are two major divisions in the pitot-static system: push its way into the diaphragm and the pressure within the 1. Impact air pressure due to forward motion (flight) diaphragm increases. -
Two-Dimensional Aerodynamics
Flightlab Ground School 2. Two-Dimensional Aerodynamics Copyright Flight Emergency & Advanced Maneuvers Training, Inc. dba Flightlab, 2009. All rights reserved. For Training Purposes Only Our Plan for Stall Demonstrations Remember Mass Flow? We’ll do a stall series at the beginning of our Remember the illustration of the venturi from first flight, and tuft the trainer’s wing with yarn your student pilot days (like Figure 1)? The before we go. The tufts show complex airflow major idea is that the flow in the venturi and are truly fun to watch. You’ll first see the increases in velocity as it passes through the tufts near the root trailing edge begin to wiggle narrows. and then actually reverse direction as the adverse pressure gradient grows and the boundary layer The Law of Conservation of Mass operates here: separates from the wing. The disturbance will The mass you send into the venturi over a given work its way up the chord. You’ll also see the unit of time has to equal the mass that comes out movement of the tufts spread toward the over the same time (mass can’t be destroyed). wingtips. This spanwise movement can be This can only happen if the velocity increases modified in a number of ways, but depends when the cross section decreases. The velocity is primarily on planform (wing shape as seen from in fact inversely proportional to the cross section above). Spanwise characteristics have important area. So if you reduce the cross section area of implications for lateral control at high angles of the narrowest part of the venturi to half that of attack, and thus for recovery from unusual the opening, for example, the velocity must attitudes entered from stalls. -
Sailplane Instrument Installation and Leak Checking
Sailplane Instrument Installation and leak checking Updated December 2008 In order to obtain the best possible performance from your sailplane instruments it is essential that the installation be done correctly and be free of leaks. A few simple installation rules are: 1. Use good quality tubing (Tygon brand is highly recommended) to connect the instruments. 2. DO NOT use very soft wall tubing for the Total energy line and make sure this line is well secured so that it cannot move under changing G loads due to manouevering and/or turbulence. This will prevent spurious transient signals on the vario caused by volume and hence pressure changes in this line. Long lengths of tubing should be of the less flexible plastic or rigid nylon pressure hose. This prevents problems with the sudden static pressure changes in the fuselage during zoom or pushover causing weird transients in the T.E. vario readings due to these pressure changes being transmitted through soft tubing in the T.E. line. Any soft wall gust filter bottles should be removed and disposed of for the same reasons. 3. All tubing must be in good condition and should be a very tight press fit over the fitting to avoid air leaks. Even a small air leak will compromise any variometer's performance. For extra insurance against air leaks we supply small, thick walled elastic 'donuts' which you may install over tubing several inches past the end. After the tubing is properly attached to the fitting on the instrument, slide the 'donut' back toward the end of the tube so that it supplies extra squeeze around the tubing/fitting area. -
The Aerodynamics of the Pitot Static Tube and Its Current Role in Non
AC 2010-1803: THE AERODYNAMICS OF THE PITOT-STATIC TUBE AND ITS CURRENT ROLE IN NON-IDEAL ENGINEERING APPLICATIONS B. Terry Beck, Kansas State University B. Terry Beck, Kansas State University Terry Beck is a Professor of Mechanical and Nuclear Engineering at Kansas State University (KSU) and teaches courses in the fluid and thermal sciences. He conducts research in the development and application of optical measurement techniques, including laser velocimetry and laser-based diagnostic testing for industrial applications. Dr. Beck received his B.S. (1971), M.S. (1974), and Ph.D. (1978) degrees in mechanical engineering from Oakland University. Greg Payne, Kansas State University Greg Payne is a senior in the Mechanical and Nuclear Engineering (MNE) Department at Kansas State University (KSU). In addition to his work as laboratory assistant on our MNE wind tunnel facility, where he has contributed significantly to wind tunnel lab development projects such as the current Pitot-static probe project, he was also the team leader for the KSU SAE Aero Design Competition in 2008. Trevor Heitman, Kansas State University Trevor Heitman is a junior in the Mechanical and Nuclear Engineering Department at Kansas State University (KSU). He worked on the Pitot-static probe project as part of his wind tunnel laboratory assistant activities, and has also contributed significantly to previous wind tunnel lab development projects including development of the smoke rake system currently in use. Page 15.1204.1 Page © American Society for Engineering Education, 2010 The Aerodynamics of the Pitot-Static Tube and its Current Role in Non-Ideal Engineering Applications Abstract The Pitot-static tube is a traditional device for local point-wise measurement of airspeed. -
Derivation of Forces on a Sail Using Pressure and Shape Measurements at Full-Scale
Derivation of Forces on a Sail using Pressure and Shape Measurements at Full-Scale Master of Science Thesis DALE MORRIS Department of Shipping and Marine Technology Division of Sustainable Ship Propulsion CHALMERS UNIVERSITY OF TECHNOLOGY Göteborg, Sweden, 2011 Report No. X-11/267 0 REPORT NO. X-11/267 Derivation of Forces on a Sail using Pressure and Shape Measurements at Full-Scale DALE MORRIS Department of Shipping and Marine Technology CHALMERS UNIVERSITY OF TECHNOLOGY Gothenburg, Sweden 2011 i Derivation of Forces on a Sail using Pressure and Shape Measurements at Full-Scale DALE MORRIS © DALE MORRIS, 2011 Report No. X-11/267 Department of Shipping and Marine Technology SE-412 96 Gothenburg Sweden Telephone +46 (0)31-772 1000 Cover: Orange neon stripes, detected by the sail recognition software VSPARS, and pressure sensors on full-scale sails Printed by Chalmers Reproservice Gothenburg, Sweden 2011 ii Derivation of Forces on a Sail using Pressure and Shape Measurements at Full-Scale DALE MORRIS Department of Shipping and Marine Technology Chalmers University of Technology Abstract Aerodynamic forces are usually computed numerically or measured in a wind tunnel. These forces may be used to predict the performance of a yacht at full-scale. The aim of this project was to develop a new method to measure the forces and moments directly at full-scale. The theory was that by simultaneously measuring the shape of the sails and the pressures around them the force normal to the surface could be derived by summation of the product of the pressure, unit normal vector and the relevant area of the discretised sail shape.