1.1 INTRODUCTION TO JETS Jet may also be defined as a pressure driven shear force which exhibits certain characteristics. When a jet is introduced into the environment it is known as free jet or submerged jet. When a jet is surrounded by a flow field of different velocity then it is termed co-flowing jet. When the jet travels farther away from the origin, it slows down due to the mixing up of jet stream with the ambient fluid entrained in the jet field. It is due to the boundary layer at the nozzle exit which progressively increases the mass flow rate when it travels downstream. In order to conserve the momentum the centreline velocity decreases towards the downstream. In the jet flows the centerline velocity remains constant as that of nozzle exit …show more content…
Mach number is a dimensionless parameter which is the square root of the ratio of the inertia force of the fluid to the elastic force of the fluid. It is important where the comparison is made between the velocity of the flow to the velocity of sound in applications like airplanes travelling at high speeds, projectiles etc. If the Mach number of the flow field is less than or equal to 0.3 then the flow field is considered as incompressible. The flow Mach number more than 0.3 is compressible. The flow can be classified as follows depending on the value of Mach number Subsonic flow Transonic flow Sonic flow Supersonic flow Flow velocity is used to classify flows according to local speed. Subsonic flows are flow fields in which the local speed is always below the local speed of sound. (M1) Compressible jets are further classified as subsonic, sonic and supersonic jets. Figure 1.3 shows the Classification of
...Another way to decrease the disturbance over the wings are to move the wings lower than the horizontal stabilizer or visa versa to allow the shock waves moving over each wing to miss each other. Most aircraft today do not have enough fuel to maintain the speed of sound for great distances. Engineers have designed a brand new aircraft known as the F-22, which has the ability to fly an entire mission at supersonic speeds. The speed of light is unattainable by aircraft due to drag. We have no materials that could with stand the heat caused by the friction of the air moving over its body, nor materials strong enough to be able to take the enormous drag. Today there is no thrust capability that would allow for the speed of light. Although aircraft has proved such things as time dilation it is still impossible for an aircraft to travel at 900,000 miles per second.
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.
The book Flight written by Sherman Alexie is about a 15 year old part Native American
Serway, Jewett. Physics for Scientists and Engineers 6th Edition. Pomona: California State Polytechnic University. 2004.
Introduction to Aerodynamics Aerodynamics is the study of the motion of fluids in the gas state and bodies in motion relative to the fluid/air. In other words, the study of aerodynamics is the study of fluid dynamics specifically relating to air or the gas state of matter. When an object travels through fluid/air there are two types of flow characteristics that happen, laminar and turbulent. Laminar flow is a smooth, steady flow over a smooth surface and it has little disturbance. Intuition would lead to the belief that this type of air flow would be desirable.
Travelling at a speed twice that of sound might seem to be futuristic; however, this feat was already achieved almost 40 years ago by the world’s only supersonic passenger aircraft, the Concorde. Concorde brought a revolution in the aviation industry by operating transatlantic flights in less than four hours. The slick and elegant aircraft with one of the most sophisticated engineering was one of the most coveted aircraft of its time. However, this was all destined to end when Air France Flight 4590 was involved in a tragic disaster just outside the city of Paris on July 25, 2000. The crash killed 113 people, but more disastrous was its impact.
When the Reynolds number is less than 10 .... it is considered laminar, when it is greater than 100 it is considered turbulent. The areas in between are defined as transitional and can go either way.
Depending of the variables used to calculate the mass air flow (pressure or air flow).
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.
Everest, F. and Pohlmann, K. 2009. Master Handbook of Acoustics. 5th ed. of the book. Johnlsayers.com.
Paper Airplanes, flight at its simplest for humans. As kids, we learned how to build paper airplanes and send them soaring into the sky. We didn't stop to think about why the airplanes where able to fly after the initial thrust we gave them or how they were able to glide for so long afterwards. Ignorance was bliss then, but now we strive to understand how things work. Looking back to the childhood past time of flying paper airplanes, I will try to explain some of the parts that make paper airplanes fly.
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.
Tillery, B. (2012). Wave Motions and Sound. Physical science (9th ed., pp. 115-134). New York,