• Extra care has to be taken so that highly skewed and negative volume elements are not generated
Unstructured Grid:
Unstructured grid can consist of any type of elements ranging from triangle, quadrilateral to tetrahedral, prism, pyramids and hexahedral.
Advantages:
• The grid density can be controlled in any region without worrying much about the density getting increased in another region
• Easy to use with complex geometries. Can be computed within an hour
• Don’t have to worry much about skewness or bad quality since the grid generation algorithm takes care of that most of the time
Disadvantages:
• Every cell can be indexed as a function of only 1 variable which causes that variable to be very large and thus increases computational load
• Causes more numerical diffusion than structured grid
Chapter 3
The scramjet model
3.1 Configurations of scramjet engine
Scramjet engines can be used as a propulsion system for cruise missiles, military aerospace planes and space launchers. Scramjet propelled aerospace plane can propel small payloads using hydro-carbon as fuel in horizontal take off SSTO (Single Stage to Orbit) and propel large payloads when using hydro carbons as fuel and when it is likely to succeed on the second stage of TSTO (Two Stage to Orbit). Different types of Scramjet engines were developed during the research on it to overcome the demerits or disadvantages of the others. The types are classified on the basis of the inlet shape, the combustor shape and the fuel injection system.
3.2 The new model
The scramjet engines model used to perform analysis has three parts as follows:
i) The inlet ramp ii) The combustion chamber iii) The outlet
3.2.1 The Isometric views of Engine model (CATIA V5)
The ...
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...terested in capturing the internal flow physics of the configuration we created structured mesh inside the engine and unstructured otherwise.
Fig. 5.2: Structured Mesh in the internal domain near the ramp wall
To capture the flow physics near the engine wall we need to increase the density of the cells near the wall. A grid was generated in the computational domain of the simulations using grid generator package ICEM cfd (Ansys 14.5). The first grid layer near the engine wall was nearly 20microns and hence the grid is finer at the walls of the engine and relatively coarser away from the walls of the engine.
Fig. 5.3: Grid finer near the wall and courser away from it (Combustion chamber)
Other than the internal section of the configuration the external domain was created with the unstructured grid. So overall the simulations were carried out using hybrid grid.
1.Intake: The intake valve opens allowing fresh oxygen rich air mixed with fuel to enter the cylinder.
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.
In this paper you will learn so much about rockets you can become a rocket specialist. Many may ask how do rockets work? Many will respond that they are pushed against something but that is wrong. Since rocket's main purpose are to travel in space where there is nothing, not even air they can not rely on “something” to push themselves against in space. This is the right answer to how rockets work; Rockets use fuel, they burn the fuel and it turns into hot gas.
The commercial cube is composed of 26 visible pieces and one central core. These two distinct components of the Rubik’s cube are what maintain the shape of the Rubik’s cube. The shape of the core can be visualized as a central, three-axis spindle with six attached octagons, one on each face of the cube. These are referred to as octagonal extensions and are what allow the free movement and rotation of the cube.
More cost-effective modes of space transportation are necessary to make further exploration possible. One new, cost effective design is the aerospace plane. These spacecraft are totally reusable and can take off and land like a normal plane (Booth 80). Anything reusable cuts costs. Many commercial spaceflight companies are interested in this design because so much money can be saved.
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.
...aints and the applied loads to the model. The rectangular composite was then basically restrained as simply supported on one side and a pressure load of 50 Mpa was applied to opposite side of the model.
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.
Wilson, D. G., & Korakianitis, T. (1998). The design of high-efficiency turbomachinery and gas turbines (2nd ed.). Upper Saddle River, NJ: Prentice Hall.
The purpose of this paper is to review on how physics can help to improve motorcycle performance. I currently own a 2003 Harley Davidson VROD. It came from the factory weighing in at 683.3 lbs (dry) or 285 kg. The VROD has a wheelbase of 67.2 inches or 1710 mm. The Engine that resides in the VROD is an 1130cc German designed performance engine developed by Porsche that has a winning stature in the racing world. The VROD is claimed to have a 115 horsepower or 86 kW of power at 8250 revolutions per minute (rpm) at the crankshaft. It also claims to have 84 foot ponds of torque or 113.9 N-m at the crank. All that information translates into that the VROD line of motorcycles are long, low, and very fast compared to other larger displacement motorcycles of that style. With such a high tech engine, I feel that more power can be tweaked out of it to help improve miles per gallon (mpg) horsepower, and torque. We will first begin with air intake performance. A stock air flow filter allows a set amount of air flow to pass thru the combustion chambers of the engine. But as we all know more ai...
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.
Cross model produces Newtonian viscosities at very low and shear rates compared to the Power Law model (Kim, 2002).
lines, rope, and plastic nets are being caught in the rutter and the engine, but
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...
lines, rope, and plastic nets are being caught in the rutter and the engine, but