Multiple Boundary Layers in Simulations
In recent years, aerodynamic simulations, such as airfoils, have become much more advanced. The invention of the computer has greatly increased aerodynamic simulation capabilities. The simulation software Sub2D, used by Consulting Aviation Services, can create airfoil simulations with multiple bodies, simulate inviscid and viscous flow, compute the separation location of an airfoil, compute the coefficients for lift, moment, and drag, and more (Flansburg). Another facet of the Sub2D software is its ability to measure the thickness and characteristics of the boundary layer of a viscous airfoil (Flansburg). This function of the Sub2D software is important in finding the coefficients of lift, drag, and moment, as well as separation coordinates, for viscous flow. To better understand the role of boundary layers in aerodynamic simulations and calculations, boundary layers, along with some other concepts, must be explained.
Boundary Layers
The book Boundary Layer Theory by H. Schlichting and K. Gersten is, to quote the back cover, “almost legendary”. What can be implied from this quote is that the book Boundary Layer Theory is authoritative in the science of boundary layer. The book begins with a conundrum faced by the Eighteenth Century scientists studying fluid mechanics. These fluid mechanics were basing all of their studies on an ideal fluid. The problem with basing studies on an ideal fluid is that in an ideal fluid, a body moving subsonically will produce no drag (Schlichting & Gersten, 2000). This paradox, known as D’Alembert’s Paradox, is a result of the dismissing of a key factor which distinguishes inviscid and viscous flow. The key factor is tangential stress, or friction, and...
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... high-lift flow with separation control by periodic excitation. Informally published manuscript, Hermann-Fottinger-Institute for Fluid Mechanics, Technical University of Berlin, Berlin, Germany. Retrieved from http://www.cfd.tu-berlin.de/~schatz/PUBLICATIONS/aiaa2001-0296.pdf
Schlichting, H., & Gersten, K. (2000). Boundary layer theory. (8 ed.). Berlin: Springer.
Stieger, R. (2002). The effects of wakes on separating boundary layers in low pressure turbines. (Unpublished doctoral dissertation, Cambridge University, Cambridge, United Kingdoms)Retrieved from http://www-g.eng.cam.ac.uk/whittle/publications/rds/RStieger_PhD.pdf
Tran, D. (2003). Comparison of numerical simulation of the flow around an airfoil in high lift configuration with piv experimental results. Berlin: Springer. Retrieved from http://extras.springer.com/2004/978-3-540-21423-6/Proceedings/p043.pdf
Ever since I was little I was amazed at the ability for a machine to fly. I have always wanted to explore ideas of flight and be able to actually fly. I think I may have found my childhood fantasy in the world of aeronautical engineering. The object of my paper is to give me more insight on my future career as an aeronautical engineer. This paper was also to give me ideas of the physics of flight and be to apply those physics of flight to compete in a high school competition.
They just forgot to mention the other effects of fluids in nature. “The influence of the fluid on a body moving through it depends not only on the body’s velocity but also on the velocity of the fluid,” this is called relative velocity ( ). The relative velocity of a body in a fluid has an effect on the magnitude of the acting forces. For example, as a long distance runner is running into a head wind, the force of the fluid is very strong. If the runner is running with the help of a tail wind, the current’s force is reduced and may even be unnoticeable.
Boeing Ltd. has initiated a project that will improve the design aircraft. This design will provide a safer and more comfortable flight. In conjunction with this project, Batchel...
In the project for science fair, we will be dropping whirligigs to test, which have the most aerodynamic structure. We will be recording the weight of the paper clips we put onto the whirligig. We will use the app that tracts how the whirligig falls. Which is called “Vernier Video Physics”. Then when we have enough data we will try to make the perfect paper airplane. To get the perfect paper airplane we must have the correct weight, the correct thrust, and the correct aerodynamics of the whirligig, this is why our project mostly consists of aerodynamics.
What is aerodynamics? The word comes from two Greek words aerios concerning the air, and dynamis, meaning powerful. Aerodynamics is the study of forces and the resulting motion of objects through the air. Humans have been interested in aerodynamics and flying for thousands of years, although flying in a heavier-than-air machine has been possible only in the last hundred years. Aerodynamics affects the motion of a large airliner, a model rocket, a beach ball thrown near the shore, or a kite flying high overhead. The curve ball thrown by big league baseball pitchers gets its curve from aerodynamics.
“In other words, there appeared to be a trade-off between pressure and speed: The smaller the speed, the greater the pressure, or the greater the speed, the smaller the pressure”
The trials and tribulations of flight have had their ups and downs over the course of history. From the many who failed to the few that conquered; the thought of flight has always astonished us all. The Wright brothers were the first to sustain flight and therefore are credited with the invention of the airplane. John Allen who wrote Aerodynamics: The Science of Air in Motion says, “The Wright Brothers were the supreme example of their time of men gifted with practical skill, theoretical knowledge and insight” (6). As we all know, the airplane has had thousands of designs since then, but for the most part the physics of flight has remained the same. As you can see, the failures that occurred while trying to fly only prove that flight is truly remarkable.
where p is the density of the fluid (in runner’s case: air); v is the velocity of the runner; A is the cross-sectional area perpendicular to the runner’s velocity; and D is the dimensionless quantity called the drag coefficient.
This chart shows the relationship between the fanning friction factor and the Reynolds number over a wide range of flow rates, from which the roughness parameter (e/D) for the piping system can be estimated.
On a more scientific note I am interested in mechanics of fluids. This interest was enforced last year when I had the opportunity to attend a lecture on fluid mechanics at P&G. At the conference I greatly expanded my knowledge regarding the physical aspect of fluids and their properties. In last year's AS course we have met a topic in this field. I will be applying ideas and knowledge gathered from last year for this investigation.
Saravanamutto, H. I. H., Rogers, G. F. C., Cohen, H., & Straznicky, P. V. (2009). Gas turbine theory (6th ed.). London, UK: Prentice Hall.
The aerodynamic efficiency is the single most important element in designing a competitive car for professional racing or getting the car model on the front of a Car and Driver or Motortrend. Aerodynamics is the study of the motion of gases on objects and the forces created by this motion. The Bernoulli effect is one of the most important behind car design. The Bernoulli Effect states that the pressure of a fluid, in gaseous or liquid state, varies inversely with speed or velocity and a slower moving fluid will exert more pressure on and object than the same fluid moving slower (Yager). The goal of car designers is to make the air passing under a car move faster than the air passing over the car. This causes the air passing over the car to create more downforce than the air passing under the car creates upforce creating a force additional to the car’s weight pushing the car to the road. Large amounts of downforce are needed to keep light cars grounded at high speed and keep to cars from sliding around turns at high speeds.
A in November 1962, the British and French governments agreed to develop and build a supersonic aircraft. Each design presents an aerodynamic supersonic aircraft with a range of difficult problems, including two that have the highest interest powerplant installation and design of subsonic aircraft. supersonic speed because it is there are many configuration changes have been introduced, particularly in the areas of the nose and visor, rear wing and fuselage. the head of...
The wind is an incredibly valuable renewable energy source and is in the forefront of renewable energy developments. It is used to convert wind energy into energy that can be harnessed and used via a variety of methods, including; wind turbines, windmills, sails and windpumps. For a renewable energy source, however, it is wind turbines that are used to generate electricity (see figure 1). Wind power has been used for this since the end of the nineteenth century, after Professor James Blyth of the Royal College of Science and Technology first attempted it (Boyle, 2012). However, It wasn’t until the 1980s that using wind power technology was sufficient enough to experience a rapid growth of the technology.
A steam turbine's two main parts are the cylinder and the rotor. As the steam passes through the fixed blades or nozzles it expands and its velocity increases. The high-velocity jet of steam strikes the first set of moving blades. The kinetic energy of the steam changes into mechanical energy, causing the shaft to rotate. The steam then enters the next set of fixed blades and strikes the next row of moving blades. As the steam flows through the turbine, its pressure and temperature decreases, while its volume increases. The decrease in pressure and temperature occurs as the steam transmits energy to the shaft and performs work. After passing through the last turbine stage, the steam exhausts into the condenser or process steam system. The kinetic energy of the steam changes into mechanical erringly through the impact (impulse) or reaction of the steam against the blades.